試題詳解

5. A baseball is thrown vertically upward and feels no air resistance. As it is rising
(A) both its momentum and its mechanical energy are conserved.
(B) both its momentum and its kinetic energy are conserved.
(C) its kinetic energy is conserved, but its momentum is not conserved.
(D) its momentum is not conserved, but its mechanical energy is conserved.
(E) its gravitational potential energy is not conserved, buts its momentum is conserved.