A rod `PQ` of mass `M` and length `L` is hinged at end `P`. The rod is kept horizontal by a massless string tied to point `Q` as shown in the figure. When string is cut, the initial angular accleration of the rod is.

Options

A. `(3 g)/(2 L)`
B. `(g)/(L)`
C. `(2 g)/(L)`
D. `(2 g)/(3 L)`

Answer

A

Explanation

(a) Taking torque about `P`
`Mg((L)/(2)) = ((M L^2)/(3)) prop`
Hence `prop = (3 g)/(2 L)`.
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