Physics

Problem

A boy of mass

50\,\text{kg}

standing on a smooth horizontal surface pushes a girl of mass

40\,\text{kg}

who is standing at rest on roller skates. After the push, the boy moves backward with a speed of

0.6\,\text{m/s}

. What is the girl's speed immediately after the push? a)

0.67\,\text{m/s}

forward b)

0.75\,\text{m/s}

forward c)

0.48\,\text{m/s}

forward d)

0.60\,\text{m/s}

forward