A boy of mass is standing on a frictionless skateboard

PHYSICS · Subjective · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

A boy of mass

60\,\text{kg}

is standing on a frictionless skateboard. He throws a

2\,\text{kg}

ball horizontally forward with a speed of

5\,\text{m/s}

relative to the ground. Calculate the recoil speed of the boy immediately after the throw.