Linear momentum is conserved in
a. an inelastic collision.
b. an elastic collision.
c. any collision where two objects rebound off each other.
d. none of the above.
[Ques. 2] A mechanic working on a 100-m radar tower drops a hammer weighing 44.5 N. The work done on the hammer as it falls is
a. 4.45 N-m. b. 44.5 N-m.
c. 445 N-m. d. 4,450 N-m.
[Ques. 3] The mass of 1 cubic meter of fresh water at the top of a 100 m hydroelectric dam is 1,000 kg and it has a potential energy of 980,000 N. At the bottom of the dam, the speed of the moving water is
a. 9,800 m/s. b. 1,960 m/s.
c. 44.3 m/s. d. 98 m/s.
[Ques. 4] The mass of 1 cubic meter of fresh water is 1,000 kg. At the top of a 100 m hydroelectric dam the potential energy of the cubic meter of water is
a. 10,000 N. b. 98,000 N.
c. 100,000 N. d. 980,000 N.
[Ques. 5] The mass of 1 m3 of fresh water is 1,000 kg. At the top of a hydroelectric dam the potential energy of the water is
a. 1,000 N. b. 9,800 N.
c. 500 N. d. There is not enough information to calculate the potential energy.
[Ques. 6] A kid slides down an icy (frictionless) hill starting from rest. At the top his gravitational potential energy is 500 J.Suppose after reaching the bottom he then continues sliding up another icy slope on the other side of the valley. When he finally comes to a stop he will have reached a height
a. equal to the height he started from on the other hill.
b. less than the height he started from on the other hill.
c. more than the height he started from on the other hill.
d. none of the above
[Ques. 7] A kid slides down an icy (frictionless) hill starting from rest. At the top his gravitational potential energy is 500 J.He slides all the way down to the valley bottom where his gravitational potential energy becomes zero. His kinetic energy at the bottom will be
a. 0 J. b. 500 J.
c. some value between 0 and 500 J. d. none of the above.
[Ques. 8] A kid slides down an icy (frictionless) hill starting from rest. At the top his gravitational potential energy is 500 J.He slides part way down the hill to a point where his gravitational potential energy is 200 J. His kinetic energy at that point will be
a. 200 J.
b. 300 J.
c. some unknown value between 0 and 500 J.
d. none of the above.
[Ques. 9] A kid slides down an icy (frictionless) hill starting from rest. At the top his gravitational potential energy is 500 J.His kinetic energy at the top of the hill is
a. 0 J. b. 500 J.
c. some value between 0 and 500 J. d. none of the above.
[Ques. 10] An object moving in a circle at a steady speed has
a. constant linear momentum.
b. constant angular momentum.
c. constant velocity.
d. constant acceleration.
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