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A machine which is 75 % efficient uses 1...

A machine which is 75 % efficient uses 12 J of energy lifting up a 1 kg mass through a certain distance . The mass is then allowed to fall through that distance. What will be its velocity at end of fall:

A

`sqrt(24) m//s`

B

`sqrt(32) m//s`

C

`sqrt(18) m//s`

D

`sqrt(19) m//s`

Text Solution

Verified by Experts

The correct Answer is:
c
Work done =`(75)/(100)xx12=9 J`.
`1/2mv^(2)=9impliesv=sqrt((2xx9)/(1))=sqrt(18)ms^(-1)`.
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