A light and a heavy object have the same momentum.

K.E. $=\frac{p^{2}}{2 m}$

For same momentum $(p), K . E . \alpha \frac{1}{m}$

$\therefore \frac{(\text { K.E }) \text { light object }}{(\text { K.E. }) \text { heavy object }}=\frac{\text { mass of heavy object }}{\text { mass of light object }}>1$

Thus, K.E. of light object > K.E. of heavy object.