Ball `A` is dropped from the top of a building. At the same instant ball `B` is thrown vertically upwards from the ground. When the balls collide, they are moving in opposite direction and the speed of `A` is twice the speed of `B`. At what fraction of the height of the building did the collision occurs ?

Options

A. `(1)/(3)`
B. `(2)/(3)`
C. `(5)/(3)`
D. `(7)/(3)`

Answer

B

Explanation

`(h_(B))/(h_(A)+h_(B))=(ut-(1)/(2)g t^(2))/((1)/(2)g t^(2)+(ut-(1)/(2)g t^(2)))`