【单选题】A ball of clay falls freely to the hard floor. It does not bounce noticeably, and it very quickly comes to rest. What, then, has happened to the energy the ball had while it was falling?It has been us...
A.
It has been used up in producing the downward motion.
B.
It has been transformed back into potential energy.
C.
It has been transferred into the ball by heat.
D.
It is in the ball and floor (and walls) as energy of invisible molecular motion.