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A body of mass 1000 kg is lifted up by a...

A body of mass 1000 kg is lifted up by a crane through a distance 15 min 1 minute. A second crane does the same job in two minute. What is the amount of work done by each crane and what is the ratio of their powers? `(g=10m//s^(2))`

A

`15xx10^(4)J,1:2`

B

`15xx10^(3)J,2:1`

C

`15xx10^(4)J,2:1`

D

`10xx10^(4)J,1:2`

Text Solution

Verified by Experts

The correct Answer is:
C
Power = Rate of doing work
`=(mgh)/(t)=((m)/(t))xx g xx h`
`therefore P=15xx10xx60=9000 W`
But 10% energy is lost done to friction.
`therefore` Actual power generated `=9000xx(90)/(100)`
`=8100 W=8.1 kW`
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