140 likes | 161 Views
KE and PE Practice Quiz. Solutions. 1. Kinetic energy is dependent on the mass of the object and its speed (velocity). 2.
E N D
KE and PE Practice Quiz Solutions
1. Kinetic energy is dependent on the mass of the object and its speed (velocity).
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 kx2 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.
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
4. T = tension W = weight = mg
KE = ½ mv2 KE = ½ (16)(1.6)2 KE = 20.48 Joules
6. a. GPE = mgh = (2.4)(9.8)(2) = 47.04 J b. GPE = mgh = (2.4)(9.8)(0.8) = 18.82 J c. GPE = mgh = (2.4)(9.8)(0) = 0 J d. GPE = KE mgh = ½ mv2 47.04 = ½ (2.4)v2 v2 = 39.2 v = 6.26 m/s
7. GPE = mgh 19.6 = (0.5)(9.8)h h = 4 m
8. KE = ½ mv2 12 = ½ m (2)2 m = 6 kg
9. F = kx F = (10 N/m) (0.25) m F = 2.5 N PE = ½ kx2 PE = ½ (10)(.25)2 PE = 0.3125 J
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.
11. W = Fd W = mgd W = (30)(9.8)(8) W = 2352 J
12. W = Fd 3.2 = F (0.8) F = 4 N
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