試題詳解

79. Two stones, one of mass m and the other of mass 2m, are thrown directly upward with the same velocity at the same time from ground level. Assume the air resistance can be neglected. Which statement about these stones is true?
(A) Both stones will reach the same height because they initially had the same amount of kinetic energy.
(B) The heavier stone will go twice as high as the lighter one because it initially had twice as much kinetic energy.
(C) At their highest point, both stones will have the same gravitational potential energy because they reach the same height.
(D) At its highest point, the heavier stone will have twice as much gravitational potential energy as the lighter one because it is twice as heavy.