Physics

Problem

A smooth ball

P

of mass

0.2\,\text{kg}

moves rightward with speed

10\,\text{m\,s}^{-1}

and collides elastically with another ball

Q

of mass

0.3\,\text{kg}

moving in the same direction at

5\,\text{m\,s}^{-1}

. Immediately afterwards,

Q

hits a fixed smooth wall and rebounds with a coefficient of restitution

e=0.5

. What is the speed of

Q

just after rebounding from the wall? a)

9.0\,\text{m\,s}^{-1}

2.25\,\text{m\,s}^{-1}

4.5\,\text{m\,s}^{-1}

6.0\,\text{m\,s}^{-1}