Question

A heavy steel ball of mass greater than 1 kg moving with a speed of 2 $mse{c}^{-1}$collides head on with a stationary ping-pong ball of mass less than 0.1 gm. The collision is elastic. After the collision the ping-pong ball moves approximately with speed

• A. $2mse{c}^{-1}$
• B. $4mse{c}^{-1}$
• C. $2\times {10}^{4}mse{c}^{-1}$
• D. $2\times {10}^{3}mse{c}^{-1}$

Answer 1

The correct option is B

$4mse{c}^{-1}$

We know that when heavier body strikes elastically with a lighter body then after collision lighter body will move with double velocity that of heavier body.i.e.the ping pong ball move with speed of $2\times 2=4m/s$