31. A shopping cart slows as it moves along a level floor. Which statement describes the energies of the cart?

(1) The kinetic energy increases and the gravitational potential energy remains the same.(2) The kinetic energy increases and the gravitational potential energy decreases.(3) The kinetic energy decreases and the gravitational potential energy remains the same.(4) The kinetic energy decreases and the gravitational potential energy increases.

32. Two identically-sized metal spheres, A and B, are on insulating stands, as shown in the diagram below.

Sphere A possesses an excess of 6.3 × 1010 electrons and sphere B is neutral. Which diagram best represents the charge distribution on sphere B?

33. Two points, A and B, are located within the electric field produced by a −3.0 nanocoulomb charge. Point A is 0.10 meter to the left of the charge and point B is 0.20 meter to the right of the charge, as shown in the diagram below.

Compared to the magnitude of the electric field strength at point A, the magnitude of the electric field strength at point B is

(1) half as great(2) twice as great(3) one-fourth as great(4) four times as great

34. The diagram below represents two waves, A and B, traveling through the same uniform medium.

Which characteristic is the same for both waves?

(1) amplitude(2) frequency(3) period(4) wavelength

35. The diagram below shows a periodic wave.

Which two points on the wave are 180.° out of phase?

(1) A and C(2) B and E(3) F and G(4) D and H

36. The height of a 30-story building is approximately

(1) 100 m(2) 101 m(3) 102 m(4) 103 m

37. Two identically-sized metal spheres on insulating stands are positioned as shown below. The charge on sphere A is −4.0 × 10−6 coulomb and the charge on sphere B is −8.0 × 10−6 coulomb.

The two spheres are touched together and then separated. The total number of excess electrons on sphere A after the separation is

(1) 2.5 × 1013(2) 3.8 × 1013(3) 5.0 × 1013(4) 7.5 × 1013

38. A 1.0 × 103-kilogram car travels at a constant speed of 20. meters per second around a horizontal circular track. The diameter of the track is 1.0 × 102 meters. The magnitude of the car’s centripetal acceleration is

(1) 0.20 m/s2(2) 2.0 m/s2(3) 8.0 m/s2(4) 4.0 m/s2

39. Which combination of units can be used to express electrical energy?

40. The total amount of electrical energy used by a 315-watt television during 30.0 minutes of operation is

(1) 5.67 × 105 J(2) 9.45 × 103 J(3) 1.05 × 101 J(4) 1.75 x 10-1 J

41. Which graph best represents the relationship between the absolute index of refraction and the speed of light (f = 5.09 × 1014 Hz) in various media?

42. A 25-gram paper cup falls from rest off the edge of a tabletop 0.90 meter above the floor. If the cup has 0.20 joule of kinetic energy when it hits the floor, what is the total amount of energy converted into internal (thermal) energy during the cup’s fall?

(1) 0.02 J(2) 0.22 J(3) 2.2 J(4) 220 J

43. Which electron transition between the energy levels of hydrogen causes the emission of a photon of visible light?

44. Which graph best represents an object in equilibrium moving in a straight line?

45. A body, B, is moving at constant speed in a horizontal circular path around point P. Which diagram shows the direction of the velocity (v) and the direction of the centripetal force (Fc) acting on the body?

46. Which graph best represents the relationship between photon energy and photon wavelength?

49. When a ray of light traveling in water reaches a boundary with air, part of the light ray is reflected and part is refracted. Which ray diagram best represents the paths of the reflected and refracted light rays?

50. The graph below represents the work done against gravity by a student as she walks up a flight of stairs at constant speed.

Compared to the power generated by the student after 2.0 seconds, the power generated by the student after 4.0 seconds is

(1) the same(2) twice as great(3) half as great(4) four times as great