Which of the following is not a perfectly inelastic collision

Options

A. an electron captured by a proton
B. a bullet striking a ball of sand
C. striking of two glass balls
D. a man jumping into a moving cart

Answer

C

Explanation

The ball strikes the ground with a velocity v and `v^(2) = 2gh` …..(1)
The velocity of rebound = ev
For the upward motion, `0 = (ev)^(2) - 2gh'`
`:. e^(2) v^(2) = 2gh'` …..(2)
`:. e^(2). 2gh = 2gh'`
`:. h'=e^(2) h = 0.8 xx 0.8 xx 1 = 0.64m`