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A machine which is 75% efficient, use 12...

A machine which is 75% efficient, use 12 J of energy in lifting 1 kg mass through a certain height. The mass is then allowed to fall through the same height.Find the velocity at the end of its fall.

A

`sqrt24`

B

`sqrt32`

C

`sqrt18`

D

`sqrt9`

Text Solution

Verified by Experts

The correct Answer is:
C
75% of 12 J = 9 J
mgh `= 9 implies h = 9/(1xx10) = 0.9 m`
`v=sqrt(2gh)=sqrt(2xx10xx0.9)=sqrt(18)m//s`
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