Q47 / 105 · NTA Abhyas (JEE Main) 2020 · Physics · Center of Mass Momentum and Collision

A ball of mass m moving with velocity v strikes the bob of a pendulum at rest. The mass of the bob is also m . If the collision is perfectly inelastic, the height to which the bob will rise is given by  h = v 2 x.g , then x=?

Correct answer: 8

Solution

Because the collision is perfectly inelastic, hence the two blocks stick together. By conservation of linear momentum,
  2 mV = mv   or V = v 2

By conservation of energy,

 2mgh= 1 2 2m V 2 2   or h = v 2 / 8 g
 x=8

Hence, the correct answer is 8.

More Center of Mass Momentum and Collision Questions