Question

A 0.5 kg ball traveling at 6 m/s collides with a 1-kg ball that was moving in the opposite direction at 12 m/s. The 0.5-kg ball moves away at 14 m/s in the opposite direction after the collision. Find the velocity of the 1-kg ball after the collision.

Answer 1

Explanations & Calculations

• By the conservation of linear momentum,

$\qquad\qquad \begin{aligned} \small 0.5\times6ms^{-1}-1\times12ms^{-1}&=\small -0.5\times14ms^{-1}+1\times v\\ \small 3.0-12&=\small -7+v\\ \small v&=\small -2\,ms^{-1} \end{aligned}$

• Therefore, the ball $\small 1kg$ ball moves on the opposite direction to its original direction at a speed os $\small 2\,ms^{-1}.$