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A man places a chain (of mass m and leng...

A man places a chain (of mass `m` and length `l`) on a table slowly. Initially, the lower end of the chain just touches the table. The main brings down the chain by length `l//2`. Work done by the man in this process is

A

`-mgl/2`

B

`-(mgl)/4`

C

`-(3mgl)/8`

D

`-(mgl)/8`

Text Solution

Verified by Experts

The correct Answer is:
C
The work done by man is negative of magnitude of decreases in potential energy of chain

`DeltaU=mgL/2-m/2 g L/4=3mgL/8 :. W=-(3mg l)/8`
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