A very broad elevator is going up vertically with constant acceleration of `2" m/s"^(2)`. At the instant when its velocity is 4 m/s a ball is projected from the floor of the lift with a speed of 4 m/s relative to the floor at an elevation of `30^(@)`. The range of ball over the floor of the lift is :

Options

A. `(1)/(2)s`
B. `(1)/(3)s`
C. `(1)/(4)s`
D. 1s

Answer

B

Explanation

Ley us see the motion relative to elevator,
`a_(r) = a_(b) = (-10) -(+2) =- 12 ms^(-2)`
Now, `T = (2u_(y))/(a_(r)) = (2 xx u sin theta)/(a_(r)) = (2 xx 4 xx sin 30^(@))/(12) = (1)/(3)s`