1.

In the given figure `F=10N, R=1m`, mass of the body is `2kg` and moment of inertia of the body about an axis passing through `O` and perpendicular to the plane of the body is `4kgm^(2)`. `O` is the centre of mass of the body. If the ground is smooth, what is the total kinetic energy of the body after `2s`?A. `100J`B. `75J`C. `50J`D. `25J`

Answer» Correct Answer - C
Net torque `tau=F2R-FR=FR`
`alpha=tau/I=(FR)/I=(10xx1)/4=2.5rad//s^2`
After `2s:omega=alphat=2.5xx2=5rad//s`
`KE=1/2Iomega^2=1/2xx4(5)^2=50J`
There will be no translation as acceleration of centre of mass will be zero.


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