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The weight of a man standing on a weighi...

The weight of a man standing on a weighing machine in a lift is noted when (i) the lift is moving with a uniform velocity and (ii) the lift is moving down with an acceleration a. The ratio of the two weights is `4/3`. What is the value of a

A

`a=g/2`

B

`a=g/3`

C

`a=g/4`

D

`a=g/5`

Text Solution

Verified by Experts

The correct Answer is:
C
When the lift is moving with uniform velocity (or is at rest), the weighing machine gives the true weight mg but when the lift moves downwards with an acceleration a (where a lt g), the apparent weight becomes `m(g-a)`.
`therefore (4)/(3) = (mg)/(m(g-a))`
`therefore 4g-4a= 3g therefore g=4a or a = (g)/(4)`
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