Physics

Problem

5\,\text{kg}

block slides to the right at

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

on a smooth surface while a

1\,\text{kg}

block moves to the left at

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

. They collide head-on and the collision is perfectly elastic. The speed of the

1\,\text{kg}

block immediately after the collision is a)

-5.3\,\text{m\,s}^{-1}

+5.3\,\text{m\,s}^{-1}

+1.2\,\text{m\,s}^{-1}

-6.3\,\text{m\,s}^{-1}