Physics

Problem

0.40\,\text{kg}

puck slides on friction-free ice at

3.5\,\text{m}\!\cdot\!\text{s}^{-1}

and collides head-on with a

0.60\,\text{kg}

puck initially at rest. The pucks stick together. Calculate the percentage of the system’s initial kinetic energy that is lost in the collision.