Two identical 7-kg bowling balls roll toward each other. The one on the left is moving at +4 m/s while the one on the right is moving at -4 m/s. What is the velocity of each ball after they collide elastically?
a. Neither is moving.
c. +4 m/s, -4 m/s
b. -14 m/s, 14 m/s
d. -4 m/s, +4 m/s
[Ques. 2] If a negative charge is placed inside a hollow isolated conductor that is originally neutral and the charge does not touch that conductor at any time:
a. both the inner and outer surfaces will become negative.
b. both the inner and outer surfaces will remain neutral.
c. the outside surface of the conductor will become positively charged. d. the inside surface of the conductor will become positively charged.
[Ques. 3] A neutron in a nuclear reactor makes an elastic head-on collision with a carbon atom initially at rest. (The mass of the carbon atom is 12 times that of the neutron.) What fraction of the neutron's original kinetic energy is retained by the neutron?
a. 14.4
c. 41.4
b. 28.4
d. 71.6
[Ques. 4] We have a hollow metallic sphere with charge +5.0 C and radius 5.0 cm. We insert a -10 C charge at the center of the sphere through a hole in the surface. What charge now rests on the outer surface of the sphere?
a. +10 C
c. -5 C
b. +5 C
d. +15 C
[Ques. 5] Two skaters, both of mass 75 kg, are initially at rest on skates on a frictionless ice pond. One skater throws a 0.3-kg ball at 10 m/s to his friend, who catches it and throws it back at 10 m/s. When the first skater has caught the returned ball, what is the velocity of each of the two skaters?
a. 0.08 m/s, moving apart
c. 0.08 m/s, moving towards each other
b. 0.04 m/s, moving apart
d. 0.04 m/s, moving towards each other
[Ques. 6] We have an initially uncharged hollow metallic sphere with radius of 5.0 cm. I place a small object with a charge of +40 C at the center of the sphere through a hole in the surface. Find the electric field present at a point 10 cm from the sphere's center. (ke = 8.99 109 Nm2/C2)
a. 9.0 106 N/C
c. 2.3 106 N/C
b. 1.1 106 N/C
d. 36 106 N/C
[Ques. 7] A tennis ball is held above and in contact with a basketball, and then both are simultaneously dropped. The tennis ball bounces off the basketball at a fairly high speed. This is because:
a. the basketball falls farther than the tennis ball.
b. the tennis ball is slightly shielded from the Earth's gravitational pull.
c. the massive basketball transfers momentum to the lighter tennis ball.
d. the tennis ball has a smaller radius.
[Ques. 8] An initially uncharged hollow metallic sphere with radius of 5 cm has a small object with a charge of -10 C carefully placed at the center of the sphere through a hole in the latter's surface. What charge resides inner surface of the sphere?
a. -10 C
c. +10 C
b. zero
d. -4000 C
[Ques. 9] Kaitlin uses a bat to hit a thrown baseball. She knocks the ball back in the direction from which it came in an inelastic collision. The bat, which is heavier than the baseball, continues to move in the same direction after the hit as Kaitlin follows through.. Is the ball moving faster before or after it was hit?
a. The ball was moving faster before it was hit.
b. The ball was moving faster after it was hit.
c. The ball was moving at essentially the same speed before and after the hit.
d. There is insufficient information to answer this problem.
[Ques. 10] An initially uncharged hollow metallic sphere with radius of 5 cm has a small object with a charge of -10 C carefully placed at the center of the sphere through a hole in the latter's surface. With the charge in place, what charge is now present on the outside surface of the sphere?
a. zero
c. +4000 C
b. -10 C
d. +10 C
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