A chain of mass m and lenght l is placed on a table with one sixth of it hanging freely from the table edge. the amount of work done to pull the chain on the table is?

Asked by rekkakr1095 | 26th Nov, 2010, 01:00: PM

Expert Answer:

Dear student
Let λ is the linear mass density of chain. To pull the chain we have to do work against the weight of hanging part of the chain.
Let at any instant length of the hanging part is x. Therefore, the weight of the hanging pat of chain is
W = λxg
The work done in pulling the chain by small diatance dx
dw = - λxg dx
total work done to pull the whole of hanging part of the chain is
w = ∫dw =  ( limit from l/6 to 0 )∫- λxg dx
or, w = λgl2 /  2(6)2 = mgl /  2(6)2 = mgl / 72
We hope this clarifies your doubt.

Answered by  | 27th Nov, 2010, 03:49: PM

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