48. Two opposite charges +q and -q are located as the right figure shows. What is the resulting electric field at points on the y axis?
  
(A)
(B)
(C)
(D)
(E)0

44. Four objects are released from rest at the top of an inclined plane and roll down the plane (see the figure). A is a solid sphere. B is a hollow sphere, C is a solid cylinder, and D is a hollow cylinder. All of the four objects have identical radii and masses. Assume that the objects roll without slipping. Which one would win the race?(A) A (B) B (C) C (D) D (E) AIl arrive at the end of the inclined plane at the same time. 

45. Knowing that a particle of mass m in a potential will do a simple harmonic motion as x(t) = X cos(ωt +Φ), where x(t) is the position of the particle with time. What will be the angular frequency for a particle of mass 2m when it moves in this potential? (A)ω(B)2ω (C)ω/2(D) (E)

46. Assuming a satellite orbits a planet in a perfect circle with radius r. If the mass of the satellite is Ms and the mass of the planet is MP, what is the speed of the satellite orbiting the planet? (G is the gravitational constant.) (A)(B)(C)(D)(E)

47. If an amount of heat Q can increase the temperature of a solid metal sphere of diameter D from 10℃ to 12℃. What is the amount of heat needed to increase the temperature of a solid sphere of diameter 2D of the same metal from 100C to 16℃? (A)Q(B)3Q (C)6Q (D) 24Q (E) 48Q

49. What is the capacitance of a parallel plate capacitor? Assume A is the area of each plate, ε is electric constant and d is the distance between plates. (A)(B) (C)(D)(E)

50. A magnetic flux is through the conducting loop according to the relation ΦB(t) = 6t2 + 7t, whereΦB is in milliwebers and t is in seconds. What is the magnitude of the emf induced in the loop when t =2.0 s? (A) 38mV (B) 30 mV (C) 31 mV (D) 15 mV (E) 15.5 mV

51. The intensity of electromagnetic energy 3 m from the point source is 100 W/m2. What is the intensity 30 m away? (A) 1000 W/m2 (B) 100 W/m2 (C) 10 W/m2 (D) 1 W/m2 (E) 0.1 W/m2

52. If the distance between the first and the tenth minima of the double-slit pattern is 18.0 mm and the slits are separated by 0.150 mm with the screen 50.0 cm from the slits, what is the wavelength of the light used? (A) 400 nm (B) 500 nm (C) 600 nm (D) 700 nm (E) 800 nm

53. A 29.5-kg boy standing still on a frictionless surface catches a 500-g dodgeball with velocity = (20.0 m/s). What is the total energy loss of the system(the boy and the dodgeball)? (A) 16.7 J (B) 48.0 J (C) 98.3 J (D) 67.6 J (E) Not enough information

54. A block with mass 0.5 kg is forced against a horizontal spring of negligible mass, compressing the spring with a distance of 0.2 m. When the block is released, the block moves on a horizontal tabletop for 1.0 m before coming to rest. The force constant of the spring is 100 N/m. What is the coefficient of kinetic friction between the block and the tabletop? (A)0.16(B) 0.25 (C)0.32(D) 0.41 (E) 0.53