A 1.0-kg object moving in a certain direction has a kinetic energy of 2.0 J. It hits a wall and comes back with half its original speed. What is the kinetic energy of this object at this point?
A) 2.0 J
B) 1.0 J
C) 0.50 J
D) 0.25 J
E) 4.0 J
C
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Which of the following is a true water "wave", as that word is used in physics?
A) Ocean waves coming in to a beach B) Ripples on the surface of a pond C) Both of the above. D) Water flowing down a river E) All of the above.
A comet is discovered in an elliptical orbit around the sun. Its closest distance from the sun is 1.0 AU, and measurements of its speed at this distance imply that its greatest distance from the sun is 7 AU. About how many years will pass between the comet’s approaches to the sun?
A. 8 y B. 16 y C. 22.6 y D. 64 y E. 226 y F. Other (specify)
Which of the following is a result of Earth rotating on its axis?
A) The occurrence of day and night B) The lunar phases C) The yearly cycle D) The occurrence of solar eclipses
Without telescopes or other aid, we can look up and see the Moon in the night sky because it
A) emits thermal radiation. B) reflects infrared light. C) reflects visible light. D) glows through radioactive decay. E) emits visible light.