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On a disc of radius R a concentric circl...

On a disc of radius `R` a concentric circle of radius `R//2` is drawn. The disc is free to rotate about a frictionless fixed axis through its center and perpendicular to plane of the disc. All three forces `(` in plane of the disc `)` shown in figure are exerted tangent to their respective circular periphery. The magnitude of the net torque `(` about centre of disc `)` acting on the disc is `:`

A

`1.5FR`

B

`1.9FR`

C

`2.3FR`

D

`2.5FR`

Text Solution

Verified by Experts

The correct Answer is:
A
Torque `tau=(2F)R+F((R)/(2))+FR(-1)`
`=(3FR)/(2)`
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