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A ball is thrown vertically downwards fr...

A ball is thrown vertically downwards from a height of 20m with an intial velocity `v_(0)`. It collides with the ground, loses 50% of its energy in collision and rebounds to the same height. The intial velocity `v_(0)` is (Take, g =10 `ms^(-2)`)

A

10 `ms^(-1)`

B

14 `ms^(-1)`

C

20 `ms^(-1)`

D

28 `ms^(-1)`

Text Solution

Verified by Experts

The correct Answer is:
C
`0.5(mgh+(1)/(2)mv^(2))=mgh`
`0.25mv^(2)=0.5mgh`
`v=sqrt(2gh)`
`=sqrt(2xx10xx20)=sqrt(400)=20m//s`
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