Physics

Problem

A smooth steel sphere of mass

2\,\text{kg}

slides with speed

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

along the

x

-axis on a frictionless horizontal floor. It collides elastically with a stationary sphere of mass

3\,\text{kg}

. After the collision, the

2\,\text{kg}

sphere is observed to move at an angle of

60^{\circ}

above the

x

-axis. The speed of the

2\,\text{kg}

sphere immediately after the collision is closest to a)

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

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

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

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