Correct Answer - A::C
In the figure, `h=R (1-cos theta)`
(a) As the mass comes down, potential energy will decrease. Hence,
`DeltaU = - mgh = - mgR(1 - costheta)`
(b) Magnitude of decrease in potential energy = increase in kinectic energy
`:.` Kinetic energy`=mgh`
`=mgR(1-cos theta)`
(c) `1/2mv^(2)=mgR(1-costheta)`
`:. v=sqrt(2gR(1-cos theta))`.
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