MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1)
A freight car moves along a frictionless level railroad track at constant speed. The car is open on
1)top. A large load of coal is suddenly dumped into the car. What happens to the velocity of the car It remains the same. It increases. It decreases. cannot be determined from the information given 2)
Tightrope walkers walk with a long flexible rod in order to
2) A) lower their center of mass.
B) move faster along the rope. C) allow both hands to hold onto something.
D) increase their total weight. 3)
Which of the following is a false statement
3) The center of mass of an object must lie within the object. The center of gravity of an object may be thought of as the balance point. For a uniform symmetric object, the center of mass is at the center of symmetry. For an object on the surface of the Earth, the center of gravity and the center of mass are the same point. 4)
In a game of pool, the white cue ball hits the 9 ball and is deflected at a 35 angle to the original
4)line of motion. What is the angle of deflection below the original line of motion for the 9 ball A) 90
D) 55 5)
In a game of pool, the white cue ball hits the 5 ball and stops, while the 5 ball moves away with 5)the same velocity as the cue ball had originally. The type of collision is elastic. completely inelastic. inelastic. any of the above, depending on the mass of the balls. 6)
Two cars collide head-on on a level friction-free road. The collision was completely inelastic and 6)both cars quickly came to rest during the collision. What is true about the velocity of this systemscenter of mass A) It was never zero.
B) It was not zero, but ended up zero. C) It was always zero.
D) none of the above 7)
Two objects collide and stick together. Kinetic energy
7) is definitely conserved. is definitely not conserved. is conserved only if the environment is frictionless....
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