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An escalator is moving downwards with a ...

An escalator is moving downwards with a uniform speed u, A man of mass m is running upwords on it at a uniform speed V. If the height of the escalator is h, the work done by the man in going up the escalator is

A

Zero

B

mgh

C

`(mghv)/(v-u)`

D

`(mghv)/((v-u))`

Text Solution

Verified by Experts

The correct Answer is:
D
Relative speed of man with respect to escalator ` = (v-u)`
`therefore` Actual displacement of man per second ` = (v-u)`
Hence, the actual displacement of man is going up the escalator of height h is `(vh)/((v-u))`. Therefore, work done ` = mg xx (vh)/((v-u))`
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