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A 50 kg girl is swinging on a swing from...

A 50 kg girl is swinging on a swing from rest. Then, the power delivered when moving with a velocity of `2ms^(-1)` upwards in a direction making an angle `60^(@)` with the vertical is

A

490`sqrt3W`

B

490 W

C

`490sqrt2W`

D

245 W

Text Solution

Verified by Experts

The correct Answer is:
C
Two forces are acting on bob, tension and weight. Power of tension will be zero and that of weight is,

`P="mgv cos"(90^(@)+theta)`
`=-"mgv sin 60"^(@)`
`=-50xx9.8xx2xx(sqrt3)/(2)`
`=-490sqrt3W`
`therefore` Power delivered is `490sqrt3W`.
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