1. KE and PE Practice Quiz
Solutions

2. 1.
Kinetic energy is dependent on the mass of the object and its speed (velocity).

3. 2.
Spring potential energy is a form of elastic potential energy and is dependent of the property of the materials such as rubber bands and metal springs. Its equation is PE = ½ kx 2 where k is the spring constant and x is the distance stretched. Gravitational potential energy is energy of position. Its equation is PE = mgh where m is the mass of the object, g is the gravitational acceleration due to gravity, and h is the height of the object with respect to some reference point.

4. 3.
a. The order of kinetic from greatest to the least D, E, C, F, B, G, A b. The order of gravitational potential energy from greatest to least is A, G, B, F, C, E, D Notice: the order of PE compared to the order of KE

5. 4.
T = tension
W = weight = mg

6. KE = ½ mv2 KE = ½ (16)(1.6)2 KE = 20.48 Joules

7. 6.
a. GPE = mgh = (2.4)(9.8)(2) = J b. GPE = mgh = (2.4)(9.8)(0.8) = J c. GPE = mgh = (2.4)(9.8)(0) = 0 J d. GPE = KE mgh = ½ mv = ½ (2.4)v2 v2 = 39.2 v = 6.26 m/s

8. 7.
GPE = mgh 19.6 = (0.5)(9.8)h h = 4 m

9. 8.
KE = ½ mv2 12 = ½ m (2)2 m = 6 kg

10. 9.
F = kx F = (10 N/m) (0.25) m F = 2.5 N PE = ½ kx2 PE = ½ (10)(.25)2 PE = J

11. 10.
a. W = Fd W = (95)(15) W = 1425 J b. Same amount of net work on the suitcase because he is moving at a constant velocity which means the net force is 0 N applied over 15 meters is still 0 J of work on the suitcase.

12. 11.
W = Fd W = mgd W = (30)(9.8)(8) W = 2352 J

13. 12.
W = Fd 3.2 = F (0.8) F = 4 N

14. 13.
a. W = Fd W = mgd W = (200)(9.8)(2) W = 3920 J (both do the same amount of work) b. Atlas  P = W/t = 3920 / 1 = 3920 W Hercules  P = W/t = 3920 / 3 = 1307 W Winner: Atlas