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A very broad elevator is going up vertic...

A very broad elevator is going up vertically with a constant acceleration of `2m//s^(2)`. At the instant when its velocity is `4m//s` a ball is projected form the floor of the lift with a speed of `4m//s` relative to the floor at an elevation of `30^(@)`. Time taken by the ball to return the floor is `(g=10ms^(2))`

A

`1/2s`

B

`1/3s`

C

`1/4s`

D

`1s`

Text Solution

Verified by Experts

The correct Answer is:
B
Components of velocity of ball relative to lift are:
`u_(x)=4 cos 30^(@)=2sqrt3m//s`
and `u_(y)=4sin 30^(@)=2m//s`
And acceleration of ball relative to lift is `12m//s^(2)` in negative `y`direction or vertically downwards.Hence time of flight is `1//3sec`.
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