Name: ______Period: ______Date: ______

Work, Power, Kinetic and Gravitational Potential Energy

1. Work is a measure of ______and requires both ______and ______on an object.

2. ______force refers to the force that one puts into a machine and can be decreased if the machine has a ______advantage.

3. ______force refers to the force that a machine produces and is also equal to the weight of the object being lifted.

4. Since work is a measure of energy transfer, both work and energy are measured in the SI unit of ______.

5. ______is the rate or speed of doing work and is measured in ______.

6. ______mechanical advantage of a machine is the mechanical (force) advantage without ______.

7. Stored energy or energy due to position is known as ______energy.

8. Energy of motion is known as ______energy.

9. On object’s ______is one variable that affects both its potential and kinetic energy.

Show your work (all 3 steps) for ALL of the following calculations:

Calculate the input force of these inclined planes. Use the formula: Fin = Fout / FA

10. A 4000 N object lifted with an inclined plane whose FA=10.

11. A 15,000 N car with a ramp that has a FA of 25.

12. A 2000 N object lifted with an inclined plane whose FA = 5.

Calculate the work done for the following problems: W = F × D

13. Calculate the work done with the lever if the end of the lever moves 0.50 m and the force is 100 N.

14. Calculate the work done by the lever if the weight is lifted 0.20 m and the force is 400 N.

15. A screwdriver is used to pry open a lid on a paint can. The handle of the screwdriver moves 0.30m. An input force of 100 N is required to move the handle.

16. A slave on an ancient Roman warship pulls his oar a distance of 1.5 m with an input force of 450 N.

Gravitational Potential Energy: PE = m x g x h (use free-fall acceleration, g=9.8 m/s2)

17. What is the gravitational potential energy associated with a 75 kg tourist at the top floor of the Sears Tower in Chicago, with respect to the street 436 m below?

18. Calculate the potential energy of a rock with a mass of 55 kg while sitting on a cliff that is 27 m high.

19. A 10 kg mass is lifted to a height of 2 m. What is its potential energy at this position?

Kinetic Energy: KE = ½ mv2

20. A baseball is pitched with a speed of 35 m/s. If the baseball has a mass of 0.146 kg, what is its kinetic energy?

21. A cheetah can run briefly with a speed of 31 m/s. If a cheetah with a mass of 47 kg runs at this speed, what is his kinetic energy?

Calculating Power: P = W / t

22. A set of pulleys is used to lift a piano of 1,000 N. The piano is lifted 3 m in 60 seconds. How much power is used?

23. How much power is used if a force of 35 N is used to push a box a distance of 10 m in 5 seconds?

24. What is the power of a kitchen blender if it can perform 3,750 J of work in 15 seconds?