A uniform rod of mass m length `l` is attached to smooth hinge at end A and to a string at end B as shown in figure. It is at rest. The angular acceleration of the rod just after the string is cut is :

Options

A. `(3g)/(2l)`
B. `(3g)/(4l)`
C. `(5g)/(4l)`
D. `(5g)/(2l)`

Answer

B

Explanation

At the instant string is cut :
`"mg"(l)/(4)=(ml^(2))/(3)alpha rArr alpha=(3g)/(4l)`