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A spring balance fastened to the roof o...

A spring balance fastened to the roof of a lift accelerating upwards indicates `120 N` as the weight of a `80 N` body. The acceleration of the lift is `(g = 10 m//s^(2))`.

A

`5 m//s^(2)` upwards

B

`(20)/(3) m//s^(2)` upwards

C

`(10)/(3) m//s^(2)` upwards

D

`5 m//s^(2)` downwards

Text Solution

Verified by Experts

The correct Answer is:
A
`m (g + a) = 120 " " mg = 80`
`mg + ma = 120 " " m = 8`
`80 + ma = 120`
`ma = 40`
`a = (40)/(8) = 5 m//s^(2)`
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Knowledge Check

  • A person is sitting in a lift acceleration upwards, Measured weight of person will be

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