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A balloon is at a height of 81 m and is...

A balloon is at a height of 81 m and is ascending upwards with a velocity of 12 m/s . A body of 2kg weight is dropped from it. If `g = 10 m//s^(2)`, the body will reach the surface of the earth in

A

1.5s

B

4.025s

C

5.4s

D

6.75 s

Text Solution

Verified by Experts

The correct Answer is:
C
`h = ut+ 1/2 g t^2`
`rArr 81 = -12t + 1/2 xx 10t_2`
`rArr 5t^2 - 12t - 81 = 0 rArr t= 5.4 sec`
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