Two objects moving along the same straight line are leaving point `A` with an acceleration `a`, `2 a` and velocity `2 u, u` respectively at time `t = 0`. The distance moved by the object with respect to point `A` when one object overtakes the other is :

Options

A. `(3 u^2)/(a)`
B. `(2 u^2)/(a)`
C. `(4 u^2)/(a)`
D. `(6 u^2)/(a)`

Answer

D

Explanation

Let both will meet at point `B`.
`x = 2ut + .^1//_2 at^2 rArr x = ut + (1)/(2) (2a) t^2`
So `2 ut + (1)/(2) at^2 =ut + at^2`
`ut = (1)/(2) at^2 rArr t = (2u)/(a)`
So `x = 2u((2u)/(a)) + (1)/(2) a((2u)/(a))^2 = (6u^2)/(a)`.