A heavy truck moving with a velocity of `60 km//h` collides with a light drum at rest. If the collision is elastic, then the velocity of the drum immediately after collision will be

Options

A. zero
B. `60km//h`
C. `120 km//h`
D. `30km//h`

Answer

C

Explanation

In elastic collosion of a very heavy body with a light body at rest, the hearvier body continues to move with its initial velocity, but velocity of lighter body becomes twice the velocity of hearvier body.
`:. upsilon_(2)=2u_(1)=2xx60km//h=120km//h`