PREVIOUS UNITS REVIEW _______/32 Tell which scientist did the following. Choose from: Aristotle, Copernicus, Galileo or Newton. 1. Did the cannonball experiment and dropped 2 cannonballs off the leaning tower of Piza? __________________________ (1pt) 2. Developed the theory that the Earth traveled around the Sun, had to work in secret to avoid persecution and published his ideas on his death bed? __________________________ (1pt) 3. Did experiments with friction and inclined planes and said that if friction were absent, a moving object would need no force to keep it moving? _________________________(1pt) 4. Was the Greek scientist that studied motion and divided it up into natural motion and violent motion. __________________________ (1pt) 5. Which scientist developed 3 Laws of Motion? _________________________(1pt) Tell which Law of Motion fits each description below. (1st Law, 2nd Law or 3rd Law) 6. Which Law of Motion states that the acceleration produced by a net force equals that force on the object divided by the mass? (1pt) 7. Which Law of Motion says that objects at rest, stay at rest and objects in motion stay in motion in a straight line and at a constant speed, unless a force acts on it? (1pt) 8. Which Law of Motion explains why your fist hurts when you punch a wall? (1pt) 9. Which Law of Motion is called the Law of Inertia? (1pt) 10. Which Law of Motion explains why people in an automobile accident suffer whiplash? (1pt) 11. Which Law of Motion explains why a helicopter can hover over a town, even though the Earth is rotating? (1pt) 12. Which Law of Motion explains why it is harder to accelerate a heavier object? (1pt) 13. Which Law of Motion explains why an inflated balloon will fly around the room when released and the air comes out. (1pt) 14. Which Law of Motion explains why it takes longer to stop the front runner traveling at 60 mph than it does to stop a car traveling at 60 mph? (1pt) 15. Suppose an object on the Earth weighs 800 N when it is a distance of 3 radii from the center of the Earth. If it is moved so that it is on the Earth (so 3 times closer) how much would it weigh? ( 1pt) 16. The Pith ball below has a static charge of +2. Which way will it move if it hangs freely, but the charges rods next to it cannot move? (1pt) ______________ Explain Why (1pt) _________________________ 17. By how much will the total electrical force on the ball change if the rod on the right is moved 2 times farther away? (as shown below) (1pt) __________________________________ 18. You are traveling down the road on a school bus at 40 mph. Your friend is sitting next to you. How fast do you see your friend traveling? (The frame of reference is the bus) (1pt) 19. You are traveling down the road on a school bus at 40 mph. A car passes the bus from behind (in the outside lane) at 60 mph. How fast do you see the car traveling as it passes the bus? (1pt) 20. You are traveling down the road on a school bus at 40 mph. If you toss a ball straight up, where will it land? (1pt) Explain why using one of Newton’s Laws. (1pt) 21. Draw a vector diagram below that shows the following information: (5pts) 1) A 400 kg object is on a flat surface. 2) The Weight is 400 x 9.8 = 3920 N. 3) The Normal Force is 3920 N 4) There is a force of 2000 N. pushing on the object to the right. 5) There is a force of Friction acting in the opposite direction (to the left) of 500 N. Which Law of Motion explains how to solve for the acceleration? (1pt) How fast will the object accelerate? (4pts – formula, work, answer, label) CONCEPT REVIEW WORKSHEET ______/18 (use your Power Point notes to help with this worksheet) 1. a. What is Newton’s 3rd Law? (1pt) b. Give 2 examples of the 3rd Law. (2pts) 2. a. Which has the greater mass – a heavy truck at rest or a toy car rolling down the sidewalk? (1pt) b. Which has the greater momentum? (1pt) 3. a. Write the formula for Impulse. (1pt) b. If you increase the time that the same force is applied to an object, (apply the force over a longer time) does this increase or decrease the impulse? (1pt) c. Will this give more or less change in momentum? (1pt) 4. In a car crash, why is it good for the driver to extend the time during which the collision is taking place? (1pt) 5. If the time of impact in a collision is extended by four times, by how much is the force of impact changed? (1pt) 6. a. What is the Law of Conservation of Momentum? (1pt) b. In terms of momentum conservation, why does a gun kick (recoil) when fired? (1pt) 7. a. What is an elastic collision? (1pt) b. Give an example of an elastic collision. (1pt) 8. a. What is an inelastic collision? (1pt) b. Give an example of an inelastic collision. (1pt) 9. You can’t throw a raw egg against a wall without breaking it, but you can throw it with the same speed into a sagging sheet without breaking it. Explain why? (1pt) 10. Why are you hurt less if you fall on a floor with “give” than on a rigid floor? (1pt) READING GUIDE pp. 326 – 335 ______/37 1. An object’s _______________ tells you how much inertia it has (1) 2. Objects in motion have ______________________ also (1) 3. An objects momentum tells you what? (1) 4. Why is a fast moving softball harder to catch than a slow moving one? (1) 5. Why is an iron shot harder to catch than a softball at the same speed? (1) 6. Write the equation for linear momentum and tell what each letter stands for. (2) 7. What are the SI and English units for momentum? (2) 8. Write the formula for Newton’s 2nd Law learned in chapter 4. (1) 9. Write an alternate equation of Newton’s 2nd Law using momentum and tell what each letter means. (3) 10. State the alternate form of Newton’s 2nd Law with words. (1) 11. To change the speed and momentum of an object, a force must be applied for what? (1) 12. What is Impulse? 13. Write the English and SI units for Impulse. (2) 14. Impulse explains the importance of _________________ in many sports. (1) 15. Look at Example 7.3 then solve the following: In a penalty kick, a soccer player increases the speed of a ball from 0 to 30 m/s. The mass of the soccer ball is 0.45 kg. a) What impulse does the soccer player give the ball? (4) b) If the player’s foot is in contact with the ball for 0.14 seconds, what is the average force exerted on the ball? (4) 16. A force is an _______________ between 2 objects (1) 17. State Newton’s 3rd Law of Motion (1) 18. Newton’s 3rd Law says that forces always come in ____________, sometimes called ______________ and ___________________ forces. (3) 19. A closed system on which no net external forces act is called what? (1) 20. No matter what internal interactions take place in a closed isolated system, its linear momentum __________________ ____________________ (1) 21. State the Law of Conservation of Momentum (1) 22. When you use conservation of momentum to solve a problem, what 2 things do you need to define the system boundary? (2) MATH AND CONCEPT PRACTICE WORKSHEET _____/46 1. A person pushes on a large box with a force of 500 N. The box does not move. Draw a vector diagram (with arrows) to show this situation. (1pt) With how much force does the box push back on the person? (1pt) 2. A light hanging from a chain on the ceiling weighs 40 N. Draw a vector diagram to show this situation. (1pt) How much force does the chain exert on the light? (1pt) 3. When a 160 pound man steps from a 20 ton cruise ship onto a dock, the only apparent movement is the man’s, the ship doesn’t seem to move. However, if he steps off a rowboat onto a dock, he may fall into the water if the boat is not tied up securely. Explain why these situations are different using the Law of Conservation of Momentum. (1pt) 4. An astronaut with a mass of 60 kg and a satellite with a mass of 1230 kg are “weightless” in space and right next to each other. The astronaut pushes on the satellite with a force of 35 N. A. How much force does the satellite push back on the astronaut? (1pt) B. Determine the acceleration of the astronaut. (4pts – formula, work, answer, label) C. Determine the acceleration of the satellite. (4pts – formula, work, answer, label) 5. A father and his 6 year old daughter are facing each other on ice skates. With their hands they push off against one another. A. What can be said about the force on the father and the force on the daughter? (1pt) B. Which one will experience the larger acceleration? (1pt) 6. A. What does the slope of this line on the graph solve for? (1pt) B. What is the slope of the line? (label answer) (2pts) C. If the mass increased, but the momentum stays the same, what will happen to the slope of the line? (1pt) 7. A. A car with a mass of 1200 kg moves at a speed of 90 km/hr. What is its momentum? (4pts – formula, work, answer, label) B. Another car has the exact same momentum, but only a mass of 800 kg. What speed is it traveling? (4pts – formula, work, answer, label) 8. A net force accelerates a 75 kg skier from 1.0 m/s to 6.5 m/s over a time interval of 20 seconds. A. Find the initial momentum and final momentum of the skier. (4pts – answer, label for each) B. What is the change in momentum? (∆P) (1pt) C. Using the formula F=∆P t Find the force acting on the skier to cause the acceleration. (3pts – work, answer, label) 9. Coal is transported to electrical generating plants in railroad cars. An empty coal car with a mass of 9000 kg coasts at a speed of 2.5 m/s. An 18,000 kg load of coal with no horizontal velocity is dropped into the car. A. What is the momentum of the empty coal car? (4pts- formula, work, answer, label) B. What is the momentum of the coal before it drops? (1pt) C. What must be the total momentum of the car after the coal is combined with it? (1pt) D. At what speed does the car and coal combination coast? (4pts – formula, work, answer, label)

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