Two identical smooth balls are projected from points `O` and `A` on the horizontal ground with same speed of projection. The angle of projection in each case is `30^(@)`.The distance between `O` and `A` is `100 m`. The balls collide in mid-air and return to their respective points of projection. If the coefficient of restitution is `0.7`, find the speed of projection of either ball (in `m//s`) correct to nearest integer. (Take `g = 10 ms^(-2)` and `sqrt(3)=1.7)`

Answer

`38m//s`

Explanation

The collision does not alter the vertical component of the velocity of either ball so `t_(1)+t_(2)=T`
`implies50/(ucos30^(@))+50/(0.7ucos30^(@))=(2usin30^(@))/10impliesu~~38m//s`