1. art and entertainment
2. visual art and design
3. drawing

AP Physics Laboratory Manual (COVER) 2013‐2014 Intentional Blank Page
Great Neck South
AP Physics Lab Manual
01-
Introductory Materials
Scale Drawing, Angle Measure, Smart Labs
A01-02
B01-B16
6a 678-
Spark timer notes for acceleration lab 6
Acceleration with Car and Spark Timer
Free Fall
Projectile - ??? - TBD
XT1-XT3
G01-G09
H01-H06
12 13 -
Centripetal Force
Measuring Power
M01-M06
N01-N05
80 min
15 16 17 -
Springs - Hooke's Law and Potential Energy
Conservation of Momentum and Collisions
Static Electricity Lab
P01-P05
Q01-Q05
R01-R04
80 min
21 -
Simple Circuit Investigation Lab
V01-V04
80 min
24 -
Pendulum Lab
Y01-Y06
80 min
26 27 -
Speed of Sound
Refraction with Laser
AA1-AA2
AB1-AB6
40 min
APPENDIX
28 - Buoyancy
29 - Newtons Laws Super Lab
TOC
40 min
80 min
40 min
80 min
AD1-AD2
AE1-AE5
40 min
40 min
80 min
80 min
40 min
80 min
Intentional Blank Page
TOC
Making A Graph Using Excel 2007 Step 1) Type in your data without units. X data goes in column A and Y data goes in column B Step 2) Click on the 1st number under “A” and select both sets of data (image below shows selected data) Step 3) Choose the Insert Tab Step 4) Select the Scatter type Plot Step 5) Choose the plot that makes points only A01
Step 6) – Graph is made – But there is no line and no Title or axis labels. Change the Chart Layout by clicking the first layout option button Titles are now shown on the chart (as seen below) Step 7) Change the titles and axis labels. Double click the title you want to change, type your new title, hit enter. Be sure to put units with the values on the axis and make the chart title using the proper Y vs X notation. Step 8) Add a trendline – Right click any one of the data points and choose the add trendline options. When the format trendline option box opens, move it to the side so you can see your graph and try the different trendline types to see which one fits your data the best. Sometimes it is linear, but sometimes a curved trendline is a better fit, try them all to see the best one. Special Note: In this same format trendline box you will see a check box at the bottom labeled “Display Equation on Chart”. This will put the equation of the line of your graph on the chart and can be useful for finding slopes. Step 9) Printing – You have two options to print. If you click on the chart first, and then hit print, the chart will be printed on a whole page. Or you can copy the chart and paste it into Microsoft Word and resize it as part of another document. A02 Intro LAB 1
Scale Drawings,
Angle Measure and
Interpretation of
Lab Data
Name: ______________________________________________________________________
B1
1. Angle Measure – Using Protractors
A protractor is the device that we usually use to measure
angles.
Use of a protractor is rather simple. Be precise when using a protractor, make sure the base of the protractor
lines up correctly with the line you are measuring the angle from and be sure the point where the lines intersect is
directly in the center point of the protractor.
Often you have to extend the lines that make the angle you are measuring so that they will fall on the
scale and you can accurately read where they line up.
Using a protractor is best learned by viewing examples. Let’s look at a few examples.
You want to measure the angle in the bottom left corner of this triangle. Place the protractor as shown below. Be
sure that the point on the left corner of the triangle is in the center of the protractor and the bottom line of the
triangle is exactly lined up on the 0 degree part of the protractor
Angle we are measuring
Zero degree mark
Now all we do is look at the scale on the protractor to see where the line hits it. Note there are two scales on the
protractor along the arc (one on the top and one underneath it). Looking at our scale, we see the angle is either
62° or 122°. Looking at the triangle we know the angle is less than 90 so we choose the 62° measure.
Another protractor example.
B2
You are measuring the angle
between the two sides that
intersect at the top
You look to see where the line
intersects the scale.
This line is
on the 0
degree mark
Again you know the angle must be
less than 90 degress.
So you choose the 66 degree
measure.
66 degrees away
from the 0 degree
line
Sometimes you have to be creative to measure the angles of real life things because they can be a little awkward.
One trick you might try is to use a string in various ways so you can extend the side of something and get a
decent angle measure. You could also try to trace a portion of something on paper, or fold the paper to imitate
the angle that you want to measure.
B3
2. Scale Drawings
What is a "Scale" Drawing?
A scale drawing is a miniature version of a real life thing that is drawn to proportion so that if you took the drawing
and enlarged it to be the actual size, it would exactly resemble the real life object. When making a scale drawing
be sure to use a ruler and a protractor. Measure the lines you are going to draw, make them straight and
measure angles properly with a protractor if needed.
Making your own Scale Drawing
The distance from NY to CA is approximately 3000 miles. If you wanted to make a scale drawing of the road on
your paper, you can't make a line that is 3000 miles long. You have to establish a scale.
When making a scale drawing, ALWAYS USE THE CENTIMETERS PART OF YOUR RULER (cm). Each
centimeter is broken into 10 equal divisions and is easier to use.
The first part of making a scale drawing is choosing a scale. You should choose your scale so that your drawing
is not too small and not too large. It takes some practice and experience to choose a scale but a little trial and
error will give you an adequate drawing. You can often look at the largest dimension you need to draw to
determine what scale you should use.
In the example above with the road from NY to CA, a scale of 1 cm = 500 mi would be appropriate. With this
scale, your road would be 6 cm long.
Your scale will always be of the form
X units of the real life dimension
[ 1 cm = X ] which states that every 1 cm you draw on paper represents
B4
A SCALE DRAWING EXAMPLE
You want to draw a side view of a house on a piece of paper to scale. You measure the house and find out that it
is 45 feet long and 21 feet high.
We have to draw two lines to make the rectangle, which will be the house. I will chose a scale of [1 cm = 5 ft ]
The scale factor we just found is actually like a new conversion factor. It is telling us that (1 cm = 5 ft)
(its sort of like the conversion factors we used before such as (1 ft = 12 in), except this one is special only for this
example). We can use it the same way we used our other conversion factors in order to determine how long we
should actually draw each line on the paper.
We have to draw two lines, one that will represent the length of 45 ft and the other for the height of 21 ft. Lets
determine how long we should draw them on the page.
Length (45 ft)
⎛ 1 cm ⎞ = 9 cm
45 ft ⎜
⎟
⎝ 5 ft ⎠
Height (15 ft)
⎛ 1 cm ⎞ = 4.2 cm
21 ft ⎜
⎟
⎝ 5 ft ⎠
What we did here was use our scale factor (1 cm / 5 ft) to convert our real life
house measurements to values we could draw on paper. The first conversion
showed us that in order to make a line that would represent 45 ft .. we would
have to draw it 9 cm long. This makes sense, think about it: if every 1 cm we
draw represents 5 ft in real life .. then a 9 cm line ( 9x5 = 45 ) would be like a
45 ft line in real life, it works out.
Now that we have the paper dimensions, all we have to do is use a ruler to
So we need to draw the length of the house 9 cm long and the height of the house 4.2 cm high. Be sure to note
your scale on your drawing.
The House That Love Built
I start Fires !!
Scale
[ 1cm = 5 ft ]
(If you use a ruler and measure the house, you will see that it is drawn to scale, the man is sort of big though)
B5
3.) Introduction to Smart Labs
Science labs are based on real life data. The results and calculations made with lab data should make sense.
Labs are usually based on real life principles that work and when doing a lab write-up you should use your head
and make sure your data is good and what you are doing makes sense.
Rule #1 - Have an idea of what you are doing. If you are warming an object up, and you are taking temperature
readings that are decreasing, then chances are something is wrong. If you are taking time readings and find that
it takes 30 seconds for something to fall off the desk, something is wrong. If repeating the same task over and
over and 1 of the results is very different from the rest, something is most likely wrong with that result. Keep
these things in mind, and ask your teacher if you notice one of these abnormalities … as the year goes on, you
will be able to handle these problems yourself.
Samples
The following data was recorded in an experiment to find the velocity of a car. We observed visually in the
experiment that the car was constantly speeding up. See if you can find any errors that might exist in our
recorded data. Then read below to see what the errors actually are.
Distance of Car
5m
15 m
20 m
25 m
Time trial #1
0.25 sec
0.40 sec
0.50 sec
0.58 sec
Time trial #2
0.027 sec
0.43 sec
0.51 sec
0.60 sec
Time trial #3
0.22 sec
0.42 sec
0.89 sec
0.57 sec
Average Time
0.16 sec
1.25 sec
1.5 sec
0.59 sec
Speed (m/s)
31.25
12.00
13.33
423.7 m/s
Problems with this data
First of all we should notice the speed. In the experiment we noticed the car was speeding up, but this data
shows the car doing weird things, getting slower and such .. it doesn’t make sense. Maybe something is wrong
with our calculations, or maybe something is wrong with the data.
First row - notice time trial #2 compared to the others … it is much to small, it was most likely an error and should
be thrown out or redone if caught while doing the experiment.
Second row - the speed goes down so that doesn’t make sense - maybe our math is wrong. Look at the average
time. If we know something about averages we know this cant be correct and is a math error. If we look at the
data we see that the times don’t change very much at one given distance ... therefore, the average should be
close to any of the time values in that row. The three times 0.40, 0.43 and 0.42 are so close to each other that
the average would be close to them as well. We therefore know that the average time of 1.25 seconds is a
mistake. The person forgot to divide by three when they did the average formula.
Third row - well the speed has increased a little from last time, which is ok, but its still less than the original (there
was a mistake with the original speed to begin with so that might be the problem, but lets check it out anyway).
Look at the times in row three ... 0.50, 0.51, 0.89 ... the last time seems very different from the first two and is
probably an error. It should be thrown out for the analysis or redone if caught before the lab was over
Last row - the speed calculated in the last row seems high, that car would be moving at about 900 miles per hour.
Rule #2 - Data is not perfect, allow some discrepancy to what you think should occur, but be aware when there is
a large amount of error, something might be wrong.
Rule #3 - When comparing multiple values, if you notice that most of your values generally increase, then that is
probably a trend. If the values are more or less the same but go up and down a little bit each time, then chances
are those values should all be the same but experimental error makes them all a little different
B6
4.) Working with Graphs
Physics Labs also incorporate the use of graphs to interpret and display data. There are a number of important
facts to know when making graphs.
1.) Your graph should always be labeled with a title, axis labels, and units on the axis labels.
Distance vs Tim e
35
30
Distance (m)
25
20
15
10
5
0
0
1
2
3
4
5
6
Tim e (sec)
2.) Your graph should always have a best fit line drawn on it. (The graph shown above would loose points for
lack of a best fit line). To determine the best type of fit, simply look at your data points to see how the trend is.
In the above graph, we can see that it is clearly indicating a curve. Other data sets will indicate straight line best
fits. Never simply connect all data points.
Distance vs Tim e
35
y = e0.6931x
30
Distance (m)
25
20
15
10
5
0
0
1
2
3
4
5
6
Tim e (sec)
3.) If using Microsoft excel to make graphs, the only type of graph you should ever make is XY scatter, and you
use the one that makes points only. Then, after the graph is made, you right click one of the data points and
choose add trendline. Try out the difference trendlines to see which one fits best.
4.) Which values to place on the x and y axis is usually determined for you in a Physics lab and should not be
done simply by your choice. This is a very important point to remember: Graph types are always stated in
the form Y vs. X, and the Y axis value is always listed first with x axis value following it. For example,
B7
Distance vs. Time, means Distance is the y axis value and time is the x axis values. A graph of Density vs. Mass
would indicate Density is on the y axis. In the rare case that you have to choose x and y axis values, the
independent variable goes on the x axis. This means that the variable that is unaffected by the other quantity is
the one that you put on the x axis.
5.) Lab data is not perfect. Most of the time, your graphs will not form perfect curves or perfect lines, that is the
reason for the trendline … it draws a best fit of the data. Occasionally, an error on your part will result in a data
point that skews the graph and changes the trendline. You should be able to notice this error and in this case
you should eliminate the bad data point.
Example.
Distance vs Tim e
25
Distance (m)
20
15
10
5
0
0
1
2
3
4
5
6
Tim e (sec)
Clearly this data is indicating and upwards sloping trend, and the trendline does show that, however, it is being
skewed by the data point at 3 seconds which is clearly a mistake. The point should be removed and you should
note that you did that. The corrected graph is shown below.
Distance vs Tim e
14
12
Distance (m)
10
8
6
4
2
0
0
1
2
3
4
5
6
Tim e (sec)
B8
Intro Lab
Name: __________________
When turning in the lab, only turn in from this page forward.
The prior pages are for your reference only
1.) Find any errors or discrepancies in the data shown below. Write what these errors are on
the bottom of the page. Be sure to:
- Refer to the row with the error and state the error
- Then state what to do about it.
An experiment is being conducted in three identical jars full of water. They have three candles held underneath
them to heat the water. The temperature is recorded every minute.
ROW #
Time
Jar 1
Temperature
Jar 2
Temperature
Jar 3
Temperature
Average
temperature
1
1 min
10.06 °C
10.13 °C
10.00 °C
14.56 °C
2
2 min
13.71 °C
13.70 °C
13.71 °C
13.71 °C
3
3 min
20.25 °C
20.50 °C
20.55 °C
20.43 °C
4
4 min
16.20 °C
16.05 °C
16.15 °C
16.13 °C
5
5 min
24.40 °C
24.35 °C
24.42 °C
24.39 °C
6
6 min
28.00 °C
27.98 °C
24.89 °C
26.96 °C
7
7 min
46.60 °C
46.35 °C
46.50 °C
46.48 °C
There are not necessarily errors in every row, but there are 4 total errors in the data. (if there is a single error that
in turn causes other errors, that should be considered only one error total)
Only 1 error is a calculation error.
Other errors are based on the experiment as a whole and what you would expect the results to look like as it
progressed. (read the description of what is actually being done here)
B9
2.) The following data is from an experiment measuring pressure in Pascals and volume in cubic meters
Volume (m3)
1
2.5
4
5.75
8
Pressure (Pa)
100
40
25
17.4
12.5
(a) Based on your knowledge from chemistry and gas laws, predict what the shape of the graph Pressure vs.
Volume should look like and draw it below. Be sure to label each axis with units.
(b) Using the real lab data, create a graph of Pressure vs. Volume by hand. Again label everything. Put a best fit
line or curve on the graph.
(c) Your predicted graph and your actual graph might look very different from each other. This relationship is an
inverse relationship. The actual graph you made should be a curve and is the correct look of an inverse graph.
Some students believe an inverse looks like a straight line sloping downward; this is incorrect and will never occur
in a physics lab or test. It is very important to note that inverse graphs are always like the graph you plotted in
the grid.
B10
3.) The following data is from an experiment measuring Force in newtons and mass in kilograms.
Mass (kg)
1
2
3
4
5
6
Force (N)
10
23
29
43
50
95
Create a graph of Force vs. Mass by hand and draw a best fit line. Be sure to state any corrections here
that you need to make for lab data errors, and make those corrections.
4.) Using Microsoft excel, recreate the graphs that you made in steps 2 and 3 and attach them to the back of this lab report. Your lab should have both the hand plotted graphs draw on these last two pages as well as the computer generated graphs. Directions for excel are on the pages that follow. B11
LAB QUESTIONS … continued
1 - Measure all angles in this shape. Be as accurate as possible, you will only be given a 1 degree margin or
error.
2 - Measure the angles between the lines drawn below (you will need to extend the lines with a ruler in order to
see where they fall on the scale on your protractor, show your line extensions).
3 - Draw two lines that are separated by an angle of 35 degrees.
B12
LAB QUESTIONS
4 - Make a scale drawing of a Boat that is 25 ft long and has a sail that rises 40 ft into the air. Be sure to show the
conversions from real life measures to paper measures .. follow the steps below.
(a)
Choose a scale for your boat
State your scale factor here
(b)
[
]
Use your scale factor to convert the real life boat dimensions into paper dimensions.
Length (25 ft)
⎛
25 ft ⎜
⎝
⎞
⎟ =
⎠
⎛
40 ft ⎜
⎝
⎞
⎟ =
⎠
Height (40 ft)
Draw your scale drawing here (draw the boat). State your scale next to the drawing.
Be sure to use a Ruler to draw straight lines properly measured.
B13
… continued
(c) - Measure a TV in inches. Write down what the measurements of the TV are. Then follow the same steps as
shown above to make a scale drawing of your TV.
B14
More LAB Questions
5-
Use two of your fingers (not your thumb) to trace a V shape on the paper. When you trace the shape, it
will be sort of a U shape, use a ruler to turn it into a V shape. Now measure this angle
6-
Measure the dimensions of the top of your kitchen table in inches (be sure to use the inches side of a
ruler) Record these dimensions below (if your table is round, then just pretend it is a rectangle and
measure the longest center parts of the table, then draw it rectangular when you are done). If you don’t
have a kitchen table for some weird reason, then use a different table in the house.
Length ____________
Width
7-
____________
Measure parts of your body in inches
Length of your head
_____________
Length of your arm
_____________
Length of your leg
_____________
Length from your chin to waist
_____________
B15
8 - Make scale drawings of the table and your body.
Be sure to indicate your scale next to your drawing. Draw your body as a stick figure. Separate each arm 60°
from your torso and separate your legs by 30° from each other
B16
Introduction to Spark Timer
A spark timer is used to make accurate time and distance measurements for moving objects. To put it simply, a
spark timer is like a high tech stopwatch. It is basically a small box through which a piece of special tape is
pulled through. Inside this box, a spark is made and repeats in a known amount of time. When the tape is
pulled through the box, sparks marks are made on the tape.
Sparks made here
Tape pulled through
Since we know how often a spark is made, we can count the number of marks on the tape to see how long it
took the tape to move through. A finished tape would look something like this.
● ●
●
●
●
●
●
●
●
Using the Timer
As seen above, the timer will make a series of dots and therefore also a series of “spacings” or gaps between
dots. It is these spacings that we want to focus on. The timer is set to produce these spacings at a known time
interval. The timer can be set at either 1/60 of a second (60 Hz) or 1/10 of a second (10 Hz). When set at 1/60
of a second, this means that it takes 0.0167 seconds (1/60) to make a space. A setting of 1/10 would then mean
each space is made in 0.10 seconds.
We can easily measure a spacing with a ruler to find the distance. The time for the spacing is also known (1/60
or 1/10 sec per space depending on how the timer is set). We can therefore use this data to determine the
speed at a given spacing by finding distance over time.
Sample tape analysis: The spark timer is set at 1/60 and a motorized car pulls it through. The tape is shown
below.
● ●
●
●
●
●
●
●
●
Visual Analysis: Since the dots get farther and farther apart in the beginning, we can see that the car must be
speeding up Î logically, if each dot is made in the same amount of time and the spacing between them is
getting larger, the car must go faster for this to happen. In the second half of the tape, the dot spacing is
constant and therefore we can conclude the car was moving at a steady rate (constant speed)
Note: The spacing between each dot is what we are measuring here, not the dot itself. Therefore, we want to
count the # of dot spacings to determine the amount of time for a given distance rather than counting the # of
dots by themselves.
XT1
● ●
●
●
●
●
●
●
●
Initial and Final (Instantaneous) speed of car:
Instantaneous speeds can be assumed to be average speeds over very short time intervals.
The initial speed of the car will simply be the speed of the first spacing which can easily be found by using the
distance and time of this spacing. Likewise, the final speed will be determined using the last spacing.
For the sample tape above:
The first spacing takes 1/60 sec to make and measures 0.5 cm (.005 m).
This gives a speed of (v = d/t = 0.005 m / (1/60) sec) = 0.3 m/s
The last spacing takes 1/60 sec to make and measures 3.5 cm (.035 m)
This gives a speed of (v = d/t = 0.035 m / (1/60) sec) = 2.1 m/s
Average Velocity of the car: The average velocity of the car is defined by the total distance traveled / total time.
Using the tape, we measure the distance from the first dot to the last dot with the ruler.
Then we can count the total number of spacings and add up to get the total time
NOTE: The time used here is not 1/60 of a second, rather it is the total time.
Measured Distance = 15.4 cm
convert to m Î total distance = 0.154 m
Total # of dot spacings = 8
x (1/60 sec) per spacing Î
total time = 0.133 sec
Avg Speed
= dist / time
= 1.16 m/s
XT2
Prelab question:
A toy car has a spark timer tape attached to it and moves down a track. The timer is set to the 1/10 setting.
●
●
●
●
●
●
●
●
●
●
Visually inspect the tape above and qualitatively (no numbers) explain what the tape tells you about the motion
of the car. Explain your reasoning.
Calculate the average velocity of the car, the initial instantaneous velocity of the car, and the maximum
instantaneous velocity. (show all work with all equations and units)
XT3
Intentional Blank Page
XT4
Lab Investigation: Acceleration
Name: _____________________________
G1
Materials
spark timer
timer tape
stop watch
cart
old books and/or bricks
ramp
masking tape
Procedure
DO THIS
CATCH THE CAR
WHEN IT
REACHES THE
BOTTOM.
_____1.
Set up the apparatus shown above. DO NOT tape the timer tape to the wheel. Place the spark
timer directly on the ramp behind the car. Start with a ramp height of about 50 cm
_____2.
Rip off about 40 cm of spark tape and attach it to the car so that the outside part of tape faces up.
_____3.
Set the timer to 1/60 (60 Hz),
_____4.
Put the car at the top of the ramp, feed the spark tape in the timer and attach it to the car. Hold a
meterstick across the track in front of the car. Turn on the timer and smoothly remove the
meterstick to release the cart while your lab partner stands ready to catch it at the end of the
ramp. DO NOT USE THE STOPWATCH until step 13.
_____5.
Visually inspect the tape to make sure it makes sense as sometimes the timer can skip a dot … if
you see something strange, ask your teacher to inspect it)
_____6.
Switch places and repeat so that each person has his/her own tape.
_____7.
Draw a line through the first distinguishable dot at the beginning of the tape and label this “start”.
Draw a line through a dot towards the end of the tape and label this “end”. Be sure that the start
and end marks represents points where the car was moving on the ramp unhindered. Your tape
should look something like the picture below.
START
_____8.
END
Measure the distance between the start and end lines and make a note of it.
Start-end distance ________________
Get an average value of your whole lab group
Average distance ________________
_____9.
Cut the tape at appropriate locations and fix it to the “tape timer collection sheet” provided (keep
the tape in order when taping it to the sheet).
G2
_____10.
Return to the lab apparatus and remove the spark timer from the experiment.
_____11.
Put the car on the top of the ramp in the same spot that it started when using the timer tape.
_____12.
Put a piece of masking tape on the side of the ramp lined up with the front wheel of the car.
DO NOT PUT TAPE DIRECTLY ON THE FLAT RAMP SURFACE Using the average distance
recorded in step 8, measure down the length of the ramp that distance and put a second piece of
tape on the side of the ramp to mark the end of that distance.
_____13.
Release the car down the ramp and use the stopwatch to record the time it takes to cover the
distance between tapes (record the time from when the car starts to when the front wheel hits
the second tape)
_____14.
Repeat the drop two more times to have a total of three trials. Measure the time with the
stopwatch each time and record it.
Trial
Time
1
2
3
G3
Intentional Blank Page
G4
Acceleration of Cart Lab
Name: __________________
When turning in the lab, only turn in from this page forward.
The prior pages are for your reference only
PART A.) Timer Tape Measurements (ONLY USE THE TIMER TAPE FOR THIS PART)
1.) Use your timer tape to calculate the average velocity of the car, in m/s, over the total distance. Show and
explain work with formulas and units.
2.) Use your timer tape to calculate the instantaneous initial and final velocity of the car (this is the same as you
did in the “spark timer” lab) Show and explain work with formulas and units.
3.) Use the information in part 2 above to calculate the average velocity, in m/s:
v =
vi + v f
2
4.) Which of the two average velocity calculations performed do you think is more accurate, explain. (Don’t make
a silly statement like ‘the formula has less variable so less error’, that makes no sense. One method is more
accurate based on how it is determined and what goes into it, not based on possibility for mistakes)
G5
5.) Determine a percent error between the two calculated average velocities and use the value you consider more
accurate as the accepted value. Show formula and work with units.
6.) Using only the velocities from part 2 (vi and vf) on the previous page, and the total time of movement,
determine the acceleration of the car, show all work with formulas and units.
PART B.) Stopwatch Measurements – (use the stopwatch times as well as the distance on the ramp for this part)
1.) Find an average value of the three times recorded using the stopwatch, show work.
2.) Assume the car started from rest (vi = 0) and use the distance and time values recorded in the stopwatch part
of the lab to determine the acceleration of the car. This is just like a normal physics problem from class. List all
the known variables, pick an equation, plug in and solve.
G6
3.) In part A step 6 and in part B step 2 you calculated two different accelerations, which do you think is more
accurate, explain your reasoning
4.) Determine a percent error between the two calculated accelerations and use the value you consider more
accurate as the accepted value. Show formula and work with units.
C.) Graphs
1.) Using a ruler, measure the distance on your spark tape for the dot intervals indicated in the chart and fill in
the chart. Note that the INTERVAL NUMBER: 1,2,3 … does not represent each spacing since we are
starting from dot one each time. The time and distance should be getting significantly larger for each interval.
2.) Each dot spacing on your tape represents a given amount of time based on what the spark timer is set to, as
we learned in the spark timer lab. Use this fact to calculate the times for the intervals shown in the chart below.
Be careful because each interval has a different number of spacings. The first interval is only 1 dot spacing (dot
1-2) while the second interval is 3 dot spacings (1-2, 2-3, 3-4)
Explain how the time is calculated.
Interval
Time (s)
Distance (m)
(1) Dot 1 Æ Dot 2
(2) Dot 1 Æ Dot 4
(3)
1Æ6
(4)
1Æ8
(5)
1 Æ 10
(6)
1 Æ 12
(7)
1 Æ 14
(8)
1 Æ 16
(9)
1 Æ 18
(10)
1 Æ 20
(11)
1 Æ 22
(12)
1 Æ 24
2.) Using a computer program, make a graph of distance vs. time and attach it to this report.
(The terminology __ vs. __ tells you which value to put on the x and y axis)
G7
Questions
1.) List reasons for error in any part of this experiment. Do Not simply write “human error” or “miscalculations”
or “rounding”; those are not reasons for error. Reasons for error can include human factors, but you should
specifically state what they are rather than writing ‘human error’. Furthermore, errors are not mistakes or things
you could correct, rather they are uncontrollable and could be there no matter how many times the experiment is
conducted.
2.) The graph you created in this lab is a “d vs. t” motion curve. Based on the principles of motion curves
learned in class, what does the shape of the graph suggest about the motion of the cart. Explain your reasoning.
DO NOT SIMPLY SAY ‘as time increases distance increases’, rather analyze this graph as though it was a question
from a homework assignment on motion curves asking you to interpret what the graph tells you about what the
car is doing.
3.) In part B of the lab you calculated the acceleration of the car with the stopwatch time.
List that acceleration value here ____________________
(The following questions are just like basic kinematics word problems as we did in class, simply label all info, pick
a formula and solve)
(a) Using the value of acceleration written above, and the fact that the car started from rest, determine how fast
( in m/s) the car would be moving if it accelerated for 10 seconds, show formula and work with units.
(b) Using this same information, how long (in meters) would the ramp have to be in order to allow the car to roll
for 10 seconds, show formula and work with units.
G8
G9
Intentional Blank Page
G10
Lab Investigation: Free Fall
Name: _________________________
Procedure
PART A – Measuring your reaction time.
_____ 1.) Hold a ruler vertically and have your lab partner put their index finger and thumb at the 50 cm mark
ready to catch the ruler once it drops. Drop the ruler so it falls straight down and let your partner catch
it with the two fingers.
_____ 2.) Record the distance the ruler fell.
_____ 3.) Switch partners and get results for the whole group.
_____ 4.) Record everyone’s results and calculate their reaction times, show calculations. Tell the winner that
they are the coolest for being so quick.
Name
Distance
Reaction
Time
Do not calculate the times now. Do this once the lab is finished.
Show a sample calculation of how you did your work for one
person. Remember, this is a simple free fall problem that starts
from rest. Just like a problem in class, write down all known
variables, pick an equation and solve for the unknown.
H1
PART B – Acceleration of Gravity.
Description of Task - Use the spark timer, tape, and weight to find an experimental value of the acceleration
due to gravity. Use about 50 cm of spark timer tape.
Procedure
_____ 1.) Set the spark timer to 60 Hz. With this setting, each dot spacing gives you 1/60 of a second.
_____ 2.) Place the spark timer so that it rests horizontally on the edge of the table and overhangs slightly
_____ 3. Attach a 50 g weight to approximately 50 cm of timer tape (does not have to be exact), and feed it
into the spark timer with the proper side facing up.
_____ 4.) Turn on the timer, drop the weight on a book so that it does not mark the floor, then turn off timer.
_____ 5.) Visually inspect the tape to make sure it makes sense as sometimes the timer can skip a dot … if you
see something strange, ask your teacher to inspect it.
_____ 6.) Get one tape for each member in the group. Make sure the dots that you are going to use represent
times when the mass was freely falling.
_____ 7.) Cut the tape at appropriate locations and attach it to the tape timer collection sheet.
- - - - - - - END OF EXPERIEMENT - - - - - - -
Lab Analysis Notes:
- All measurements should be in “m” and “sec”
H2
Analysis
– be sure to organize your analysis so that it is clear and easy to follow
Part A – Reaction Time.
Return to page 1 and calculate reaction times. Show one sample calculation of how you arrived at your results.
Part B – Finding “g”
1.) DO NOT USE THE FIRST FOUR SETS OF DOTS on the timer tape. Draw a vertical line on the fifth dot that
you will use and mark it “start”. Also draw a line at the end of the tape on your last dot and mark it “end”.
2.) Measure and record the total distance traveled from “start” to “end” _________________________
3.) Velocity Calculations
Complete the values in the table below, put units in the top row with the labels. (Be sure to show sample
calculations below the table). Each single interval has the same time, but the elapsed time is the total sum of
intervals up to the interval you are looking at. USE METERS AND SECONDS, NOT CENTIMETERS. DO NOT PUT
FRACTIONS IN YOUR TABLE, USE DECIMAL NUMBERS.
Dot Spacing
Distance of
Interval
Time of
Interval
Instantaneous
Velocity
Total elapsed
time since start
1 (dot 1-2)
2 (dot 2-3)
3 (dot 3-4)
Continue for
all
spacings
4
(if you run out
of rows, you
can leave off
the remaining
dots)
Sample
Calculation:
H3
4.) Acceleration of gravity “g”
(a) Make a FULL PAGE graph of Instantaneous Velocity vs Total Time (remember what the “vs.” means). Be
sure that the time is the total elapsed time from the start to the point you are looking at and NOT the time only
for that interval you are in. Add a best fit line or curve to the graph (use excel’s trendline feature). If your best
fit is a curve (it shouldn’t be), add that trendline, however we also want to add a linear trendline as well to be
used to get an average value for the acceleration. If you have a curve, this linear line should be added by hand
as a dotted line.
(b) Using only the “v vs t” graph, determine the acceleration of the falling object using the linear trendline. Do
not use physics formulas to calculate g … we have made a V-T motion graph and we can use this to find the
acceleration just as you would on a motion curve homework assignment. DO NOT PICK A SINGLE POINT and
plug it into the acceleration equation. CLEARLY SHOW YOUR WORK AND EXPLAIN HOW YOU ARE PERFORMING
THESE CALCULATIONS OR HOW YOU GET YOUR ANSWER.
This value of g, acceleration due to gravity, will serve as our experimental value for “g”.
(c) Using only the V vs T motion graph, find the total distance traveled from the start to end. Explain how you
find it and then do it. Again use only the whole graph itself and the principles of motion curves to find the
distance, DO NOT PICK A POINT from the graph and plug into acceleration equations. Be careful when you do
this part, most students make a careless mistake getting the correct value for this.
H4
Questions
1.) List reasons for error in any part of this experiment. Do Not simply write “human error” or “miscalculations”
or “rounding”; those are not reasons for error. Reasons for error can include human factors, but you should
specifically state what they are rather than writing ‘human error’. Furthermore, errors are not mistakes or things
you could correct, rather they are uncontrollable and could be there no matter how many times the experiment is
conducted.
2.) Find the percent error of the acceleration you calculated vs. the known accepted value of g. Show work.
3.) In part 2 of the Analysis, you measured the total distance traveled by the weight. In part 4 (c) of the Analysis
you used a motion graph to calculate the total distance traveled by the weight. Find the % error of these two
calculations and use the measured value as the accepted value.
4.) You created a “v vs t” motion graph in this lab. What does the shape of this graph suggest about the
acceleration and velocity of the falling object? Describe the behavior and describe how you used the graph to get
that information. (Answer as if you were given these motion graphs on a quiz and were asked to
describe the motion of the object).
H5
H6
Intentional Blank Page
H7
Laboratory Investigation
Abstract: - Analysis of the circular motion of a swinging stopper will provide insight into the causes of
centripetal force and develop relationships between speed, radius and centripetal force.
Name: ___________________________________________
M1
Procedure:
1. Measure the mass of the rubber stopper using a scale and record in the attached data table.
2. Attach 200 g of mass to the bottom of the string that passes through the tube. Refer to the diagram to
understand how to measure the radius. Before swinging the stopper, measure the radius so that it will be
somewhere between 50-60 cm and record this value.
RADIUS USED: _______
3. Put an alligator clip on the string just underneath the bottom of the tube and wrap the string once around one
side of the clip teeth so that the clip will not slide if pushed (see diagram).
PART 1 - Changing Mass - READ UP TO STEP 5, BEFORE BEGINNING
Practice swinging
Hold the apparatus as shown in the picture and use your
free hand to hold the weight hanging below the tube.
Begin swinging in short horizontal circles to make the
stopper go in a horizontal circle around your head.
Once you get it moving, slowly release the weight in your
hand until it hangs freely.
Place
alligator clip
Vary the speed at which you swing the stopper until you
can get the alligator clip to be just below the bottom of
the tube without it touching the tube.
Keep the swing constant so that the alligator clip
remains in place and does not move up or down.
4. In this part of the lab we will be varying the mass hanging on the rope. Choose a starting mass of either 100
or 200 grams. If you are able to swing the mass successfully with the 100 gram weight, then start with that
mass, however, if the stopper is too heavy and it is difficult to swing with such a small weight then start with
the 200 gram mass.
5. We will now take data while spinning the stopper, please read the recommendations that follow, don’t be
lazy. Sometimes the stopper will be swinging quickly so be careful when you are counting the revolutions.
The person swinging the stopper usually has the best idea about the numbers of revolutions and you can
even hear the swirling noise of the stopper to help you count. The person doing the swinging can begin
counting aloud from 1 – 27, and the person timing can start the stopwatch when they hear 5, and then stop at
25 so there will be a more accurate result of the beginning and end of the 20 revolutions. Use whatever
method is best for your lab group for counting and timing. Record your data in the attached data table.
Make sure the stopper is spinning at a constant rate in a horizontal circle and the alligator clip remains at
the same spot (just below the tube but not touching), and record the amount of time required to make 20
revolutions of the stopper.
6. Repeat step 5 one more time so that you will have two trials total.
7. Add an additional 100 g of mass hanging to string to increase the total mass
Repeat the two swing trials again and record your times on the data table.
8. Add another 100 g of mass (200 g total additional added)
Repeat the two swing trials again and record your times on the data table.
9. Add a final additional 100g of mass (300 g total additional added)
Repeat the two swing trials again and record your times on the data table.
M2
PART 2 - Changing Radius
1. Copy the data from the first row of “part 1” table and make an exact copy in the first row of “part 2” data table.
2. For rows 2-4 in the part 2 table, use the initial amount of hanging mass on the string as you did in part 1, and
do not add or remove mass for any part. In this part of the lab we will vary the radius at which the stopper spins
around.
3. Move the alligator clip 10 cm up or down the rope from its current location (this will make a different radius
when the string is swung). Again wrap the string around one of the alligator teeth so that it will not slide if pushed.
Record the value of the new radius in your table.
4. Repeat the experiment as conducted before so that the clip is just barely below the glass tube and does not
move. Get the time to make 20 revolutions. Repeat this step 1 more times for a total of 2 trials.
3. Move the alligator clip to another different location (10 cm different than other trials) and record it. Measure
and record the time for 20 revolutions. Repeat this step 1 more time for a total of 2 trials.
4. Again, move the alligator to a new location (10 cm different from other trials) and record the time for 20
revolutions. Repeat this step 1 more time for a total of 2 trials.
------------------------------------ END OF EXPERIMENT -------------------------------------------------
M3
Analysis Instructions
A common mistake in this lab is misunderstanding which mass to use. There are two masses, the hanging
mass (the one hanging below the circle attached to the string) and the mass of the stopper. Each mass is used
for a different thing in the analysis. Keep in mind that the stopper is the thing that is going in the circle, so when
using circular motion analysis it is the stopper mass that is being accelerated.
Complete the calculations on the data worksheet. Read the directions below to assist you.
(a) Hanging mass weight and Fc
Why does the spinning stopper maintain its circular motion in this lab? The stopper goes in a circle because
a centripetal force allows it to happen. A centripetal force is always provided by something. In this case the
string tension provides the centripetal force. However, if there was no mass attached to the string then the
stopper would just fly away and the hanging mass creates the tension which provides the centripetal force, so
in essence the weight of the hanging mass provides the centripetal force acting on the stopper. (note,
if you are one of the few people that actually read directions, this paragraph is the basis for the answer to one
of the questions, congratulations.)
This important relationship directly gives us Fc. Now that we know the Fc we can calculate other values.
(b) Speed (V)
We are going to find the speed of the stopper with two methods and compare the results. For the purposes of
percent error, we will assume that Method 1 is the experimental value and Method 2 is the actual value.
Method 1 (experimental V) - find the speed using distance and time.
In lab we found the time needed for 20 revolutions which we can easily use to find the Period. (Period =time
needed to make 1 revolution)
We also know the distance traveled in 1 revolution. The stopper swings in a circular path and we know the
radius of this circle. The distance traveled in 1 revolution around a circle is the circles circumference C = 2 π r
With the distance and time traveled, we can find the speed of the stopper in the circle. This is method 1.
Method 2 (actual V) - find speed using the known centripetal force
In accordance with the discussion in part (a) of this analysis we know the centripetal force on the stopper. We
also know the mass of the stopper and radius of the swing. Given the formula for centripetal force:
Fnet(c) = m ac
Fnet(c) =
mv 2
r
We can see that the only unknown left in the equation is v so we can rearrange the equation to solve for v.
Read the note at the top of this page again to be sure to use the correct values.
(c) Find the percent error for the two methods of v
Graphs - Attach
1. Make a graph of centripetal force vs. speed(method 1) for part 1 of the lab
( y vs. x )
2. Make a graph of speed(method 1) vs. radius for part 2 of the lab
( y vs. x )
M4
Centripetal Force Lab
Name: __________________
When turning in the lab, only turn in from this page forward. The prior pages are for your reference only
Data and Calculations Table
ALL MASSES SHOULD BE CONVERTED TO kg
Part 1 - Constant Radius, Changing Mass
shaded columns = data to record during lab
Time for 20 revs
(s)
Hanging
Mass (kg)
Weight of
Hanging
mass (N)
Radius
(m)
Mass of
Stopper
(kg)
Trial 1
Trial 2
Average
Time
Time
for 20
for 1
revs (s) rev (s)
Fc
(N)
V
Method 1
(m/s)
V
Method 2
(m/s)
% error
V
Fc
(N)
V
Method 1
(m/s)
V
Method 2
(m/s)
% error
V
Sample Calculations:
Part 2 - Constant Mass, Changing Radius
Time for 20 revs
(s)
Hanging
Mass (kg)
Weight of
Hanging
mass (N)
Radius
(m)
Mass of
Stopper
(kg)
Trial 1
Trial 2
Average
Time
Time
for 20
for 1
revs (s) rev (s)
Questions
1.) List reasons for error in any part of this experiment. Do Not simply write “human error” or “miscalculations” or
“rounding”; those are not reasons for error. Reasons for error can include human factors, but you should
specifically state what they are rather than writing ‘human error’. Furthermore, errors are not mistakes or things
you could correct, rather they are uncontrollable and could be there no matter how many times the experiment is
conducted.
2.) Explain how you found the Fc acting on the stopper and why this is the correct way of calculating it.
3.) What does graph 1 suggest about the relationship between speed and centripetal force? Does this make
sense, explain? (you must refer to a physics formula)
4.) What does graph 2 suggest about the relationship between speed and radius? Does this make sense,
explain? (you must refer to a physics formula)
5.) Which method of solving for v do you think is more accurate and why (Don’t refer to one formula being harder
than the other, accuracy should be based on the values used to find answer, not the actual formulas themselves)
M6
Lab Investigation: Measuring Power
Name: _____________________________
N1
Introduction
The purpose of the following exercise is to measure the power you develop while first walking,
and second, running up a flight of stairs.
Power (P) = Work (W)/time (t) and W= F•d, where in the case of doing work against gravity the force used in
doing the work must be at least equal to the weight of what is being lifted
Procedure
1.)
2.)
3.)
4.)
5.)
Using the available scale, determine your weight
Now, using a stopwatch, walk up a flight of stairs and record the time it takes. Do two trials.
Using a meter stick, measure the total vertical distance you walked.
Repeat the same procedure, but run instead of walking. Do two trials
Record values for other members in the group.
Analysis and Questions
Calculations:
Separate your analysis into two separate sections, one walking section and one running section. For each section
calculate the following:
1) Convert weights in lbs to kg (1 kg = 2.2 lbs)
2) Average the two time trials for each person
3) Calculate the work done by each person
4) Calculate the power of each person in Watts
5) Convert the power to kilowatts.
6) Find averages
N2
Report
Walking
Person
Time 1
(sec)
Time 2
(sec)
Avg
Time
(sec)
Weight
(lbs)
Mass
(kg)
Weight
(N)
Distance
(m)
Work
(J)
Power
(W)
Power
(kW)
Time 2
(sec)
Avg
Time
(sec)
Weight
(lbs)
Mass
(kg)
Weight
(N)
Distance
(m)
Work
(J)
Power
(W)
Power
(kW)
Average
Sample Calculations:
Running
Person
Time 1
(sec)
Averages
N3
Questions: (show all work for calculation based questions)
1. How does the power you develop change when you run up the steps instead of walking, explain why your
answer is the way it is.
2. Examine other people’s data. What type of person seems to develop the greatest power? Did anyone reach
1 horsepower (look up the conversion if you don’t know it)
Questions 3-5 use the following information
3500 Kcal is equivalent to 1.47x107 J
3500 Kcal = 1.47x107 J
3500 Kcal expended results in 1 lb (fat) burned
or
1.47x107 J expended results in 1 lb (fat) burned
1 lb = 3500 Kcal
1 lb = 1.47x107 J
Your answers must be given by actually showing conversions from one value for another by using the above
factors and the factor label method
Recall from beginning of year, to convert ft to cm
(100 ft ) (12 in) (2.54 cm) = 3048 in
(1 ft)
(1 in)
So when answering the questions you should use a similar method only with the new factors and factors you can
make from your data table.
3. Determine how many times the average person would have to run up the steps to lose 1 pound of body fat.
The factors have been setup for you. Use your data table and the proper factors from above to fill in and get the
final answer of stair runs per lb.
( ________ J )
( 1 stair flight run )
x
=
( ________ lb )
( ________ J )
N4
3500 Kcal
1 lb
1 lb
= 1.47x107 J
= 3500 Kcal
= 1.47x107 J
4. How many Kilocalories do you estimate the average person expends in one hour of stair running? (The
question is asking you to convert 1 hr of stair runs into kilocalories of energy
( _____ runs ) ( ____ sec ) ( ____ J ) ( ____ Kcal )
x
x
x
( _____ sec ) ( ____ hr ) ( ____ run ) ( ____
J)
cancel the units above in the proper manner
Answer with unit
Kcal burned per 1 hr of stair running
_____________
5. Use the answer to question #4, and the same factor method, determine how much body fat is burned in 1
hour of stair climbing.
N5
Intentional Blank Page
N6
Spring LAB
NAME: _____________________
Hooke’s Law & Potential energy
Introduction
In this lab you will investigate the force and stretch in a variety of springs as well as investigate energy.
Procedure
Part 1 – Collecting data to determine the spring constant (see included table within lab)
DO NOT USE THE 1 kg mass, you will break the springs and rubber bands
For each spring and rubber band provided, (data table attached)
-
-
Hang the spring on a clamp and measure the initial length of the spring. (note: for the rubber band you will
have to put a small insignificant amount of weight on it to get the relaxed length, you can ignore this tiny
amount of weight in the analysis)
Attach different masses to the spring and measure the final length of the stretched spring. Each trial
should add at least 100 g of mass (for rubber band: 200g additions will most likely be needed). The
amount of mass added to the spring should be enough so that the stretch is noticeably measurable and
each trial is noticeably different.
Calculate the change in length for each mass.
Use at least 5 different masses for a given spring and repeat the process for each spring or elastic band
that is provided. You DO NOT, and probably SHOULD NOT use the same 5 masses for each spring. Make
a separate table of information for each spring.
P1
Part 2 – Energy Investigation
-
Choose one of the springs used in Part 1 and
select a mass that provided a noticeable stretch
to the spring but not so drastic that it will not be
able to be stretched further
Record the mass you will use and describe
which spring you chose to use
____________________________________
____________________________________
____________________________________
____________________________________
-
We will use the provided rings to setup the
apparatus show in the diagram, follow the steps
below:
-
Attach the mass to the spring.
-
Hold the mass so that the spring does not
stretch but will be at its relaxed length.
-
Move the top ring so that it will mark the
location of the bottom of the mass while you are
holding it at its relaxed position
READ THE WHOLE STEP BEFORE DOING IT
- DROP the mass from the relaxed length so that
it falls down and stretches the spring. Watch it
as it falls and make a note of where it
momentarily stops at the lowest position before
it bounces back up. Slide the lower ring up and
down on the stand to mark this lowest position.
REPEAT this drop a series of times until you
have accurately marked the lowest position of
the mass. THE LOWER RING SHOULD BE AT A
LOCATION BELOW THE MASS WHEN IT HAS
FINISHED BOUNCING.
-
Measure the length between the rings to get a value for the maximum stretch (change in length) of the
spring and record that value
________________________________
P2
Analysis
Part 1
1.) For one of your springs and masses, draw a FBD of the spring at its relaxed length and next to it draw a
second FBD when the mass was attached to the spring. Label the lengths and the change in length as well as
the forces acting when the mass is attached to the spring
P3
2.) Collect your data in the tables below and determine the weight ( = spring force)
Rubber Band
Mass
(kg)
FSP = FG
(N)
Initial L (xo)
(m)
Final L (x)
(m)
Δx
(m)
Spring 1 – Describe Spring Here __________________________
Mass
(kg)
FSP = FG
(N)
Initial L (xo)
(m)
Final L (x)
(m)
Δx
(m)
Spring 2 – Describe Spring Here __________________________
Mass
(kg)
FSP = FG
(N)
Initial L (xo)
(m)
Final L (x)
(m)
Δx
(m)
Spring 3 – Describe Spring Here __________________________
Mass
(kg)
FSP = FG
(N)
Initial L (xo)
(m)
Final L (x)
(m)
Δx
(m)
P4
3.) Make a separate XY scatter Graph of Force vs. Stretch for each spring and/or rubber band and be sure title
each one with the type of object used as well as the variables force and stretch (Note: you should remember how
to tell which one is the y value based on the “vs” terminology, look it up if you forgot). MAKE A SEPARATE
GRAPH FOR EACH SPRING on its own page. Be sure to put a best fit line or curve on the graph. NOTE: if
the best fit is a curve, which it probably will be for some of them, put this best fit curve in, and then after you
print the graph, draw a linear straight line to represent a representation of the average slope of the graph if the
relationship were linear. This is very important and is what you will use to find the spring constant for a graph
that is naturally curved and not linear. Some of your data might be naturally linear and not have this problem.
Make the graph sized at least a half of a piece of paper. You can copy and paste the graph from
excel into word in order to do this.
4.) Below each graph, pick appropriate points and find the slope of the graph to determine the spring constant.
Be sure to indicate which points you are using and circle them on your graph as well. (Note: DO NOT PICK
POINTS from the graph and plug into F=kx, and don’t average individual k values either. Rather
you should be finding the slope to get the spring constant).
5.) Below each graph, state whether or not the spring constant is actually constant for the spring or shows
variation based on the stretch and explain how you make this conclusion.
6.) Use each graph to determine the amount of work that would be done by the spring as mass was added. Use
the lowest amount of attached mass as the starting point and determine the work done as the spring was
stretched from this position to the final largest stretch position recorded. Clearly show your answers below each
graph and explain how you found the work in each graph.
Part 2 - The diagram below represents the motion of the spring in Part 2 of the lab. It started at rest at
position A and then was dropped until it stretched and reached position B where it momentarily stopped again.
(starting position)
\
/
\
A
hA
\
/
\
/
\
For this part of the analysis, we are going to assume that when
the spring reached position B, the max stretch, it was at a height
of zero h = 0
B (Max stretch)
(a) What kind of PE would the system posses at point A, calculate it
(b) What kind of PE would the system posses of point B, calculate it
(c) How should the results to parts (a) and (b) compare to each other. Explain in detail why they should be this
way and comment on how your results compare to what you would expect.
P5
Intentional Blank Page
P6
Conservation of Momentum in Collisions NAME: _______________________________
Q1
There are two carts; they are labeled on the side as the “dynamics cart” and the “collision cart” Perfect Inelastic Collision • The “dynamics cart” should have both the spring loader and the “Angle Indicator” attached to it which is used
to break the laser of the photogate. If they are not attached ask your teacher.
____ 1) Measure the length of the narrow middle part of the “Angle Indicator” (as shown in the diagram below)
Record the measured length here:
Length L = __________ m
L
____ 2) The “dynamics cart” should be placed on the track, with the spring launcher inserted into the black end
stop and the spring uncompressed. With the cart in this location, put one of the photogates about 10 cm away
from the front of the cart. Then put the second photogate about 50 cm away from the first photogate
(see figure 1 below)
____ 3) Adjust the height of each photogate so that the thin middle part of the Angle Indicator will be the part
that breaks the laser as the Angle Indicator moves through each photogate. You can see the location of the laser
sensor on the photogate by inspection. You must carefully set its height so that the Angle Indicator will not hit
the photogate and so that only the thin middle part passes by the laser sensor
____4) Using one of the scales in the classroom, record the mass of the Dynamics Cart. Also find the mass of
the Collision Cart and add extra 20 and 50 gram masses so that it has nearly the same mass as the dynamics
cart. Record the total masses below.
Dynamics Cart mass
m1 = ___________ kg
Collision Cart mass
m2 = _____________ kg
____ 5) Place the Collision Cart about 30 cm away from the first photogate. The location should be such that
when the dynamics cart is launched it will pass through the first photogate by itself; then collide with the Collision
Cart, and the two of them will then pass through the second photogate together.
FIGURE 1 (not to scale)
Spring launcher
Angle Indicator
Photogate 1
End Stop
Photogate 2
extra masses
Dynamics Cart
10 cm
Collision Cart
30 cm
50 cm
___6) Turn on, Reset the photogates, and make sure they are in “gate” mode
Q2
___7) Pull back on the spring launcer to compress the spring fully and release to fire the Dynamics Cart forward.
It should pass through the first photogate, collide and STICK TO the Collision cart and then both of them should
pass through the second photogate. MAKE SURE THAT THE CARTS DO NOT BOUNCE OFF THE SECOND
END STOP AND COME BACK THROUGH THE PHOTOGATES.
___8) Record your Data as follows: be sure to read carefully.
a) The time listed on the photogate at the end of the experiment is the time it took the Angle Indicator (length L)
to pass through the first photogate. We will call this t1. Record this time in the chart on the next page.
b) The photogates also record the total time that both photogates were active for (t1+t2) which can be seen by
clicking down to the “read” setting on the silver lever switch marked “memory” on the photogate (be aware that
clicking this lever will permanently erase the first time and only show the total ). This total time (t1+t2) is not
relevant to us, rather we want just time t2 (time for the Angle Indicator to pass through the second photogate).
So take the total time and subtract the first reading (t1) to get the time t2 and record it in the attached chart.
c) The velocity of each part can be found by using v= d / t with the d being the length L of the angle indicator
and the time being the individual times t1 or t2 for each photogate
___ 9) Each lab table has a series of long and short bar masses on them. Use the scales in the classroom to
determine the masses of each of these bars
Bar Masses
short _______ kg
long _______ kg
___10) Remove the small extra masses added to the collision cart previously. Add the bar masses to the carts in
different variations to create more collision trials with varying amounts of mass in each cart. Record your data
and complete the attached table with a variety of trials. (Be sure to subtract off the small mass values when
recording total mass of the collision cart)
___ 11) Determine the percent error using the initial momentum as the actual value.
Q3
Recorded Data
Trial
Total Mass
Number
(m1) of
Dynamics
Cart (kg)
Sample Calculations
Total Mass
(m2)
of
Collision
Cart (kg)
Length (L)
of Angle
Indicator
(m)
Photogate
Time (t1)
prior to
collision
(sec)
Photogate
Time (t2)
after
collision
(sec)
Calculations
Velocity (v1)
Velocity (v2)
of Dynamics of Combined
Cart prior to
Carts after
collision
collision
(m/s)
(m/s)
Total
Momentum
(p1) Before
Collision
(kg m/s)
Total
Momentum
(p2) After
Collision
(kg m/s)
Percent
Error of
Momenta
Questions
1.) Give reason for error in this experiment
2.) Did momentum conservation seem to hold true? Explain, and comment on which types of trials seem to
conserve momentum the best.
3.) (a) For trial number 1, use the recorded cart masses and initial velocity v1 of the dynamics cart to determine a
theoretical value for final velocity of the combined masses after the collision. (This calculation should be done
without the measured time t2, rather should be based on physics principles of solving collision problems) (b)
Determine the percent error of this calculated velocity vs. the measured experimental v2 from the lab data.
Q5
Intentional Blank Page
Q6
Name:
Static Electricity Lab
Introduction: Static Electricity Investigation Lab
Part A - Polarity test (+ or -)
Materials Provided
- Pith ball (small Styrofoam ball with a conductive coating allowing it to be charged)
- Rubber Rod
- Glass Rod
- Cotton Felt
- Silk
- Rabbit Fur
- Clear Acetate strip
- White Vinyl strip
Definitions:
(1) A rubber rod rubbed with fur or wool acquires a negative charge
(2) Like charges repel and opposites attract
Procedure:
1.) Using only the definitions and materials provided above. Devise a test to determine the type of charge on an
object and explain how your test will work. (The use of the pith ball is necessary every time and is the
main object to help in your test)
2.) Use your test to determine the sign (+/-) of the materials below
(a) Vinyl strip (white) rubbed with fur
(b) The fur from (a)
(c) Acetate strip (clear) rubbed with cotton felt
(d) Glass rod rubbed with silk
(e) A pen stroked on your hair.
Part B - Attraction or Repulsion
R1
(a) Use your results from PART A (Polarity test) of this lab to positively charge an object. Charge the pith ball
positively by contact. Bring a negative charge near it and then a positive charge but do not allow the charge to
touch the ball. Describe and explain the results?
(b) Discharge the pith ball completely by holding it in your hand and letting your body act as a ground. In terms
of movement of electrons, explain what happened when you touched the ball.
- Bring a negative charge near the neutral pith ball but don’t let it touch.
- Bring a positive charge near the neutral pith ball but don’t let it touch.
What results do you observe? Why does this happen?
(c) Based on the results above, which is better proof of a charged object, attraction or repulsion? Explain by
using your results from (a) and (b)
R2
Part C – Using an Electroscope
Note: When charging the electroscope by contact, it helps to rub the charged rod back and forth on the top plate
(a) Use the rubber rod and rabbit fur to negatively charge an electroscope by contact. Explain the electron flow
between the three objects (fur, rod, electroscope) that allows the electroscope to become charged
(b) Use your results from PART A (Polarity test) of this lab to positively charge an object. Bring the positively
charged object, near but not touching the negatively charged electroscope. Record your observations and
explain what you observe.
Part D – Charging by Induction
(a) Discharge the electroscope completely by using your body as a ground. Bring a charged negative rod near
but not touching the electroscope. By not touching the electroscope, no charges will be transferred from the rod.
Describe and explain the results in terms of electron flow?
(b) Move the rod away. What does the position of the pin indicate about the charge on the electroscope and why
does this happen?
R3
(c) READ THE WHOLE STEP BEFORE PROCEEDING. Bring the charged rod near again. While it is near one side
of the electroscope touch the other side with your finger. Keep your finger on it and the rod nearby. Remove
your finger from the scope first, and then remove the rod. You have now induced a charge on the scope and
should see deflection of the needle.
(d) Perform a test to determine the polarity (charge) of the electroscope. Describe what happened when you
performed this test and why this showed you what sign the charge on the electroscope was?
(e) In step C the electroscope was charged by induction. Create diagrams of each step in this process and
explain what is happening in each step in terms of electron flow.
R4
Simple Circuit Investigation Lab Name: _______________________________ Introductory Notes: Connecting Voltmeter When hooking up voltmeters to measure voltage, be aware of the following: 1) Put the meter in parallel (around) the device being measured as shown below. 2) Connect the plugs on the meter itself so that one is plugged into the “COM” port and the other to the “V” port 3) Set the meter to DC Voltage setting on the turn dial. Connecting Ammeter When hooking up ammeters to measure current, be aware of the following: 1) Put the meter in series (next to) the device being measured as shown below. 2) Connect the plugs on the meter itself so that one is plugged into the “COM” port and the other to the “10 A” port 3) Set the meter to 10A setting on the turn dial. V1 Lab Procedure / Analysis 1) Draw a schematic of a single bulb in series with a battery and an ammeter and voltmeter connected to measure current and voltage of the bulb. 2) Setup the multimeter as described on the prior page to function as a voltmeter. (be sure to connect the plugs properly and set the turn dial) 3) Single Bulb: Connect a single bulb to the battery; then connect the multimeter (voltmeter) to measure the potential of the bulb as shown on the prior page. Record results on the table on the next page. 4) Disconnect the multimeter and set it up as described on the prior page to function as an ammeter (be sure to move the plugs and set the turn dial). Connect to the single bulb and record the measured current in the data table. 5) Bulbs in series: Add a second bulb to the circuit in series. Setup the multimeter as a voltmeter (be sure to move the plugs and set the turn dial), and measure the voltage directly from the battery and directly from each bulb. Then setup the multimeter as an ammeter (be sure to move the plugs and set the turn dial) and measure the current directly after each device (battery, bulb1, bulb2). Record results. Disconnect your wires and move to step 6. 6) Bulbs in parallel are slightly harder to connect. To make measurements the easiest, it’s best to create a junction with your wires so the ammeter is very easily moved through the circuit. You will have to clip multiple wires onto each other to create these junctions, see the diagram (the wires have been numbered for you) and connect the bulbs as indicated. 7) Setup your multimeter to function as an voltmeter (be sure to move the plugs and set the turn dial) 8) After assembling your circuit, clip the multimeter (set as a voltmeter) directly in parallel with the battery to record the total voltage of the battery. Then move the voltmeter to each bulb to measure the voltage across each bulb and record results. 8) Set the multimeter to ammeter operation and connect it first directly in series with the battery, then directly in series with each bulb and measure all three currents and record them in the table that follows.
V2 Simple Circuit Lab Results
Name: _______________________________________________
DATA
Device
Voltage(V)
Current(A)
Voltage(V)
single bulb
series (2 bulbs)
parallel (2 bulbs)
battery
battery
bulb 1
bulb 1
bulb 2
sum bulb 1+2
bulb 2
sum bulb 1+2
Current(A)
Questions/Calculations
1) Referring to the results above, do the rules for current and
voltage seemed to be verified for series circuits? explain (for this question only, ignore slight variations in the data)
2) Referring to the results above, do the rules for current and
voltage seemed to be verified for parallel circuits? explain (for this question only, ignore slight variations in the data)
3) Justify any slight variations that you may have seen in voltages during the lab and in relation to questions 1&2 as to how the data compares to expected results for current and voltage in series and parallel circuits.
V3 Recopy your data from page one into this chart.
DATA
Device
single bulb
Voltage(V)
Current(A)
Voltage(V)
series (2 bulbs)
battery
bulb 1
bulb 2
sum bulb1+2
Current(A)
parallel (2 bulbs)
battery
bulb 1
bulb 2
sum bulb1+2
4) From the standpoint of the overall circuit as a whole (equivalent resistance), compare the total current flowing from the battery with the single bulb, to the total current flowing from the battery when both bulbs were connected in series, explain the results.
5) Answer question #4 for the parallel connection
6) In the space below, calculate the resistance of each bulb for each setup (show your work only for the single bulb calculation)
Single bulb
Bulb Resistance
Series bulbs
Bulb 1 Resistance
Bulb 2 Resistance
Parallel bulbs
Bulb 1 Resistance
Bulb 2 Resistance
7) Referring to the results from question 6, does the resistance of the bulb remain constant regardless of how it was connected?
Justify and explain your results.
V4 Name:
Pendulum
A pendulum swings back and forth. The motion repeats with each
swing. The concepts of cycle, period, and amplitude are used to
describe repetitive motion.
•
•
•
A cycle is one complete back and forth motion.
The period is the time it takes to complete one full cycle.
The amplitude is the amount the pendulum moves away
from its resting position.
In this experiment we will explore what
affects the motion of the Pendulum.
Setting Up
Use the string and weights to make a pendulum.
•
•
•
The clamp allows you to easily change the length of the string.
Extra weight can be added to the pendulum as you choose.
The angle of release (amplitude) can be measure and changed with a protractor
When timing pendulum swings to find the Period of motion (time for 1 swing), be sure to
use at least 10 swings back and forth to get a more accurate result
Which of the three things (length, weight, and angle) do you think has the biggest effect
on the Pendulum?
________________________________________________________________________
________________________________________________________________________
________________________________________________________________________
Y1
A: The Effect of Weight:
The first experiment looks at whether changing the weight affects the period of the Pendulum. Keep the
string length and the amplitude constant.
String length
_____________________
Weight of Bob
Amplitude
_______________________
Time For Ten Cycles
(seconds)
Period
(seconds)
Graph your data: Make sure that the scale on your x and y axis is appropriate (do not make your scale
over a very short range, rather use a normal number scale). Be sure to title it and label everything.
Also, remake this graph using Excel and attach it (you will have to adjust the axis max and min scale setting).
B: The Effect of Amplitude:
Y2
The second experiment looks at whether changing the amplitude of the swing
changes the period. Keep the string length and weight constant.
String length
_____________________
Amplitude
(degrees)
Weight of Bob
________________
Time For Ten Cycles
(seconds)
Period
(seconds)
Graph
Also, remake this graph using Excel and attach it (you will have to adjust the axis max and min scale setting).
C: The Effect of String Length:
Y3
The third experiment looks whether changing the length of the string changes the period.
Keep the weight and amplitude constant.
Amplitude
_____________________
String Length
(cm)
Weight
________________
Time For Ten Cycles
(seconds)
Period
(seconds)
Graph
Also, remake this graph using Excel and attach it (you will have to adjust the axis max and min scale setting).
Questions
Y4
1.) Which factor has the largest effect on pendulum period?
2.) Explain the actual physics reasons why each factor had or did not have an effect on the period. Do not simply
state that the factor is not in the formula, rather give actual physical reasons for each effect based on forces,
masses and the motions themselves.
------------ Continued --------------
Y5
3.) The equation for the period of a pendulum on a string is
T = 2π
l
g
Chose 1 set of results and calculate an experimental value of g based on the length of the string in that setup.
Compare (% error) the calculated value of “g” to the actual known value. Be sure to explicitly state which
measured values you are using and show all work and substitution when solving for the unknown.
Y6
Speed of Sound and Resonance
NAME: ______________________
Purpose:
The purpose of this lab is to demonstrate resonance of sound waves and determine the speed of sound traveling
in air.
Equipment
Resonance tube (graduated cylinder and inner glass tube), water, tuning forks, meter stick,
Procedure:
Velocity
elocity of sound in air
1) Fill the 1 liter graduated cylinder to within two inches from the top with water. Place the inner tube inside the
graduated cylinder.
2) Choose a tuning fork and record its frequency.
f =_________________ Hz
3) Strike the tuning fork with hard rubber and hold the tuning fork horizontally, with its tines one above the other
about 1 cm above the open end of the inner tube. Move both the inner tube and the fork up and down together
to find the air column length that gives the loudest sound. Measure the distance from the top of the resonance
tube to the water level.
Length of the resonance tube = _______________ m
4) Record the diameter of the resonance tube.
Diameter of the resonance tube = ______________ m
5) The air which vibrates and makes sound actually extends slightly beyond the length of the tube itself and we
therefore need to make a correction to find the actual length of air vibrating. This correction is made by adding
0.4 times the diameter of the tube to the measured length of the air column.
Corrected Length = _______________m
6) The vibrating air creates a fundamental standing wave in an open/closed pipe. As such,
the length of the tube measured only holds ¼ of the wavelength of the wave (see diagram).
Using this fact, determine the wavelength of the sound
(be sure to use the corrected length when doing this).
READ THIS STEP CAREFULLY, READ IT AGAIN TO
BE SURE YOU UNDERSTAND WHAT IT IS SAYING.
L
Wavelength = _______________m
7) Determine the velocity of sound and record.
show work.
Speed of sound in air = ____________m/s
AA1
8) Repeat each of the above steps for a second tuning fork:
show work.
f = ______________ Hz
Length of the resonance tube = ______________ m
Corrected Length = ______________ m
Wavelength = ______________ m
Speed of sound in air = ______________ m/s.
The accepted value for the speed of sound in air is 332m/s at 0C.
The speed of sound in air increases by 0.6m/s for each degree C above zero.
Using the temperature of the room today, compute the accepted value for the speed of sound at room
temperature.
Calculate the percentage difference between this and the average of your two measured values.
AA2
Refraction and Total Internal Reflection
Using a Laser
NOTE TO TEACHER:
Graph Paper works
much better for this
lab
NAME: ___________________________________
AB1
Materials
Handheld Laser
Ruler
Protractor
Semi-Circular dish
Refraction Procedure Part 1
1.) Take out the laser and put the batteries in. Keep the laser dry.
2.) Take a sheet of paper and place the semi-circle dish upside down in the center of the paper (open side
down). Trace the shape of the dish on the paper and remove the dish from the paper.
3.) Repeat step 2 again so you will have two sheets with tracing on them, let each lab partner trace the shape
twice as well.
4.) Fill the dish about halfway with water.
5.) Add two drops of milk to the dish and stir them into the water. The small amount of milk will make the laser
visible in the water, like fog makes lasers visible in air. Shine the laser through the side of the container to verify
that you can see it in the water, if not add a little more milk, but not too much.
6.) Place the semi-circle dish back on the traced paper shape and shine the laser directly perpendicular to the flat
face as shown in the diagram below. Keep the laser and the paper dry.
dish
paper
WHEN USING THE LASER, IT WORKS
BETTER IF YOU RAISE IT VERY
SLIGHTLY OFF THE PAPER SURFACE
SO THE LIGHT RAY DOES NOT HIT
THE BOTTOM OF THE DISH ON THE
PAPER.
laser
QUESTION:
Do you see refraction when the laser enters the dish in the configuration, explain?
AB2
7.) Using the same setup as before, change the laser orientation so that it is angled to the flat side of the dish
and hits the midpoint of the dish (see diagram). Again hold the laser slightly above the paper surface.
dish
paper
laser
QUESTION:
Do you notice refraction when the laser enters the water, explain?
8.) We are going to make 3 dots to show the path of the laser beam. Using a pencil:
1 - Place a dot (1) at the tip of the laser where the light beam originates,
2 – Place a dot (2) where the beam first hits the flat side of the dish.
(MAKE SURE THE DOT IS PLACED EXACTLY ON THE TRACED LINE, AND NOT ABOVE OR BELOW)
3 – Place a dot (3) where the beam exits the water dish
dot 3
dot 2
dot 1
9.) Remove the laser and dish and USE A RULER to connect the dots with arrowheads to show the path of the
light.
10.) Repeat so each lab partner has their own paper.
AB3
dot 2
AB4
Total Internal Reflection - Procedure Part 2
1.) Using the same setup as before, place the dish on the second traced sheet.
2.) Turn the paper around 180 degrees so that the circular side is facing you.
dish
paper
laser
In this part of the lab, the laser should always be exactly perpendicular to the curved surface.
3.) Move the laser right next to the curved surface of the dish, holding it slightly off the paper, and hold it so that
the laser light is perpendicular to the surface of the dish. Notice the light ray moving through the water and also
notice a second ray exiting the water into air at the flat side. If you cannot see the exiting ray, put something a
few centimeters behind and to the side of the flat side of the dish so you can see a dot showing where the exiting
laser goes.
4.) Slide the laser from its current position along the curved face always keeping it perpendicular to and touching
the dish, and pay attention to the ray exiting at the flat side of the dish, see diagram. The laser should be
hitting the flat side at the midpoint. Continue to move the laser until the exiting ray no longer exits the
water, but all reflects back inside, this is the critical point for total internal reflection. Slide the laser beam back
and forth to verify you have found the exact position of total internal reflection
5.) We will again make dots to mark the position of the light ray. Make one dot at the tip of the laser where the
ray enters the water, make a second dot where the laser hits the flat part of the dish, and make a third dot
where the reflected ray comes back to the curved surface
dot 2
dot 3
dot 1
6.) Remove the laser and dish, and USE A RULER, to draw the rays. Repeat for other lab partners.
AB5
AB6
ANALYSIS
Part 1 - Refraction
1.) Using your sketch from part 1, USE A RULER and draw a normal line at the flat surface and label the incident
and refraction angle on the diagram, make the normal line long so you will be able to measure the angles
properly. Accurately, measure incident and refraction angles with a protractor and use the table below to record
them. Also label them on the diagram itself.
θi
θr
2.) Using the angles above and the situation shown in the diagram, calculate a value for the index of refraction
of water. Show all formulas and work.
3.) Compare your value of nwater with the best known value nwater = 1.33. What is the % difference? Show formula
and work.
AB7
REVISED (2013)
Part 2 – Total Internal Reflection
1.) Using your sketch from part 2, USE A RULER and draw a normal line at the flat surface and label the incident
and REFLECTION angle on the diagram, make the normal line long so you will be able to measure the angles
properly. Accurately, measure incident and reflection angles with a protractor and record them in the chart
below, also record them on the diagram itself.
θi = θc
θ’
NOTE: θ’ IS NOT THE REFRACTION ANGLE.
2.) Based on the values from the chart, is the “Law of Reflection” verified, explain?
3.) The incident angle measured in step is the critical angle (θi = θc) determined experimentally since it was just
at the point where total internal reflection occurred. We are looking at the point where the laser was in
the water and was trying to get into the air, so this is the medium boundary you should be looking
at (water to air). Calculate a theoretical value for the critical angle based on the medium conditions water-air.
4.) Compare your measured experimental value of the critical angle to the theoretical actual one found in part 3,
compute a percent error and state justifications for possible error.
AB8
Buoyancy Lab Name: __________________ Purpose: Investigation of density, specific gravity and buoyancy. Procedure: Part I 1.) For each provided metal cube, use the digital scales to determine the masses. 2.) Measure the dimensions and determine the volume of each cube. 3.) Calculate the density of each cube in kg/m 3 and also determine the specific gravity of each. Make a table below to hold your values. Also show a sample calculation. (you might not use every column)
AD1 Part II 1.) Using the provided water bath and spring scale, determine the actual weight of each cube, the apparent weight of each cube in water, and the buoyant force acting on each object. 2.) Using the known value for the density of water and only the values found above, determine the volume, density and specific gravity of each object. Make a table to hold your values. Also show sample calculations. (you might not use every column) Determine a percent error between the two specific gravity results from part 1 and 2 for each cube.
AD2 Newtons Laws Super Lab Name: ____________ Part I – Static Friction 2 ways. Note: Boxed sections should be completed today. A.) Force Scale 1.) Using the digital balance; determine the mass of the cart and block separately, then put the wood block with the soft velco facing up into the dynamics cart. Record data here : mcart = ____________, mblock = ____________ 2.) Turn the cart and block upside down on the track so that the soft Velcro touches the track. 3.) Put a 1 kg hex mass on top of the upside down cart ... list new total mass here Mtotal = _______________ 4.) Using a force scale, determine the static friction maximum, repeat to verify, record data here: fs(max) = ___________ Determine the coefficient of friction from the values in part A, show work: B.) Angle of Repose (The angle of repose is the angle at which an object first begins to slip) 1.) Use the same setup as above, except, rather than using the force scale, slowly incline the dynamics track until the cart begins to slide, repeat to verify your results and record the angle: θ = __________ Determine the coefficient of friction from the values in part B , show work: Compare your answers to A and B and comment on the results
AE1 Part II – Tension in a Rope. 1.) Using two force scales and the hex mass, setup the diagram shown below with two different angles; Record the readings on both force scales, the angles, and the value of the hanging mass directly on the diagram: θ1
θ2
m
Determine a theoretical value of the tension in the ropes based on the value of the attached mass and the angles Percent Error: Find a percent error between the theoretical and experimental tensions AE2 Part III – Newtons Second LAW. Introduction to Photogates. ‐ A photogate is a laser timing device that looks like this Æ ‐ When an object passes through the laser, the photogate will record the amount of time that it takes the length of that object to pass through. Using v=d/t we laser can then determine the velocity of the object as it passes through the photogate. This is called “Gate Mode” on the photogate timer. The “d” in this scenario is the length of object breaking the laser IMPORTANT: In gate mode, both times are stored in memory in a strange fashion... When reading the values from the timer display, the first time listed will show the time it took to pass through the first gate; then if you then click the timer to the READ position, it will show the sum of both times from each gate so you have to subtract the first time value given in order to find the time for the second gate. ‐ Alternately, two photogates can be used when the photogate timer is set to “Pulse Mode”. In this mode the photogates will record the time it takes to pass from one photogate to another giving you the total time it takes to cover a fixed distance. The “d” in this scenario is the spacing of the photogates. Procedure: Setup the apparatus shown below using two photogates. ‐ Put the photogate connected to the main control box as the first one next to the cart. Use 'GATE' mode ‐ Put the ‘angle finder’ in the cart as shown and adjust the height of the photogates so that only the center of the angle indicator (marked “d” in figure) passes through the photogate laser (note: the laser location can be seen by looking at the light on the outside of the photogate near the opening). ‐ Measure and record distances “L” and “d” on the diagram below. L Angle Indicator d Cart (M2)
Photogate 1 Photogate 2
Hanging Mass M1 Experiment ‐ Use 100 g of mass for mass M1 (the hanging mass) for the entire experiment ‐ Put a variety of 100 and 200 g masses into the cart (make sure they are on their side so they don’t disrupt the photogate laser) ‐ Release the hanging mass and record the times from both photogates 1 and photogates 2 in the data table (remember, you have to subtract the second reading from the first to get the time for the second photogate, see instructions from introduction) AE3 ‐ Continually remove masses from the cart and repeat the experiment to obtain various trials. Data Table: All Data should be recorded below. Note: Experimental Acceleration is not technically 'data' as you will have to calculate it Hanging
Mass
M1
(kg)
Angle
finder
distance
"d"
(m)
Distance
between
gates "L"
(m)
Cart +
Masses
M2
(kg)
Gate 1
time - t1
(s)
Gate 2
time - t2
(s)
Experimental
Acceleration
(m/s2)
Sample Calculation: Show a sample of how experimental acceleration is calculated using the distances and times recorded from the table. Graph ‐ Create a graph of total mass (M1 + M2) vs. experimental acceleration on a full page at attach it to the lab. Since the hanging mass was kept constant, this graph will be a graph showing the relationship between mass and acceleration when the force causing the acceleration remains constant. On the graph, specifically comment about the relationship shown and whether or not it makes sense based on the second law equation and prediction of expected results.
AE4 Theoretical Acceleration ‐ Using the idealized diagram of the setup below and the recorded masses from row 1 of the lab (and assuming no friction), determine a theoretical value for the acceleration of the system showing all work. Cart(m2) hanging mass (m1) Percent Error: Find a percent error between the theoretical acceleration and experimental acceleration, comment on sources of error. AE5