TEKS 7.7A contrast situations where work is done with different amounts of force to situations where no work is done such as moving a box with a ramp and without a ramp, or standing still Calculating Work The equation to solve work problems looks like this: Work (W) = force (F) x distance (d) or W=Fxd The SI (metric) unit for force is Newton (N). The SI (metric) unit for distance is meter (m). The SI (metric) unit for work is the newton-meter which is called a joule (J). Sample Problem: A fork lift is used to lift a box and move it across a warehouse. The 1,023N box is lifted 4m. How much work is done by the fork lift? • Step 1: Write down the equation needed to solve the problem. W=Fxd • Step 2: Insert all known measurements into the equation. W = (1,023N) x (4m) • Step 3: Solve carefully. W = 4,092 J The forklift does 4,092 J of work. • Step 4: Make sure that all of your numbers have the correct SI unit label. • Step 5: Always recheck your answers. (Remember as you solve the following problems to keep following the steps shown on the previous page.) Problem #1: How much work is done by a person who uses a force of 27N to move a grocery cart 12m? Show work here: Show work here: Problem #2: If an upward force of 2,200N is used to lift a box 2 meters, how much work was Show work here: Problem #3: You and a friend apply a combined force of 500N to push a piano 3 meters. How much work was done to move the piano? Get ready for some work practice problems! Make sure to label all numbers with SI units and show all of your work. #1. Calculate the amount of work done to lift a crate weighing 567N a distance of 20m. #2. A strong wind exerts a force of 25 N on a trash can blowing it 3 m. How much work is done on the trash can? #3. A bulldozer uses a force of 2000 N to push a mound of dirt 3 m. How much work did the bulldozer do? #4. A student exerts 170 N of force to push a desk chair 4m across a floor, how much work would be done? #5. A rock climber with a weight of 150 N climbs 8 m up a rock wall. How much work did the climber do? #6. A girl uses a force of 12N to pull her sled 4m up a hill. How much work did it take to pull the sled? Bonus: A young boy applied a force of 2,550N on his St. Bernard dog who is sitting on the boy's tennis shoes. He was unable to move the dog. Explain how much work he did while trying to push the dog.
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