question_answer

A ball A of mass m falls under gravity from a height h and strikes another ball B of mass m which is supported at rest on a spring of stiffness k. Assume perfectly elastic impact. Immediately after the impact:

A) The velocity of ball A is (1/2) \[\sqrt{2}\,\,gh\]

B) The velocity of ball A is zero

C) The velocity of both balls is (1/2) \[\sqrt{2}\,\,gh\]

D) None of the above.