Part A. Multiple Choice (1K each) Select the best answer to each of the following questions. 1) A fullback running with an initial velocity of 7.2 m/s [N] swerves to avoid a tackle, and after 2.0 s is moving at 7.2 m/s [W]. His average acceleration over the time interval is a) 0 m/s', b) 5.1 m/s2 [W45.N], c) 1.0x10 m/s2 [W45'N], d) 3.6 m/s2 [S], e) 5.1 m/s2 [$45.W]. 2) A tennis ball is thrown into the air with an initial velocity that has a horizontal component of 5.5 m/s and a vertical component of 3.7 m/s [up]. If air resistance is negligible, the speed of the ball at the top of the trajectory is a) zero, b) 3.7 m/s, c) 5.5 m/s, d) 6.6 m/s, e) 9.2 m/s 3) On a windy day, you throw a football into the wind. After the football has left your hand and is moving through the air, the correct list of the forces acting on the ball is a) A force from the throw and the downward force of gravity, b) A force from the throw, a force exerted by the air, and the downward force of gravity, c) A force from the throw and a force exerted by the air, d) A force exerted by the air and the downward force of gravity, e) The downward force of gravity. 4) A child on a toboggan accelerates down a hill inclined at an angle 0 to the horizontal. Friction is negligible. The magnitude of the child's acceleration down the hill is a) g/sin 0, b) g sin 0, c) g/cos 0, d) g cos 0, e) g tan 0. 5) A rocket of mass m is at a distance of 3re from Earth's center, where re is the radius of Earth. The engines of the rocket are fired to move it to a distance of 6re from Earth's center. Upon reaching its destination, its new mass is m/2 since fuel is consumed in burn. The ratio of Earth's gravitational force on the rocket at the first location to the gravitational force on the rocket at the second location is a) 8:1, d) 1:4, b) 4:1, e) 1:8 c) 2:1, 15) 7) 9) A child pulls a sledge of mass m up the incline L long. The incline makes an angle 0 with the horizontal. The work done by gravity on the sledge during this motion is a) mgL cos 0, b} mgL sin 0, '- c) mgL cos 0, 3 d} mgL sin 0, e} None ofthe above. In an inelastic collision involving two interacting objects, the final kinetic energy of the system a) Can be equal to the initial kinetic energy ofthe system, b} Is always less than or equal to the initial kinetic energy of the system, c) Is always greaterthan or equal to the initial kinetic energy ofthe system, d} Is always less than the initial kinetic energy of the system, e} Can be greater than the initial kinetic energy of the system. When you catch a fast-moving baseball, your hand hurts less if you move it in the same direction as the ball because a) The change in momentum of the ball is less, b} The change in kinetic energy ofthe ball is less, c) The time interval ofthe interaction is less, d} The time interval ofthe interaction is greater, e} The impulse on the ball is greater. When comparing the force of attraction between an electron and a proton clue to the electric force and due to gravity, it can be concluded that a) The gravitational force is a lot stronger, b} The electric force is a lot stronger, c) The two types of forces are the same, d} The electric force is slightly stronger. 10}The magnitude of the electric field due to a small charged object is 12 NC at a distance of 3.0 m from the charge. The field 6.0 m away from the charge is a) 36 N/C, b} 12 N/C, c) 6.0 N/C, d} 4.0 N/C, e} 3.0 MG. 11}Two oppositely charged parallel plates are separated by 12 mm. The uniform electric field between the plates has a magnitude of 3.0>