A boy of mass is standing on a frictionless skateboard facing a wall

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

Problem

A boy of mass

40\,\text{kg}

is standing on a frictionless skateboard facing a wall. He pushes the wall with a horizontal force of

100\,\text{N}

for

0.20\,\text{s}

. Find the speed with which the skateboard (and the boy) starts moving just after the push.