Question

A uniform rod of mass m and length l hinged at its its end is released from rest when it is in the horizontal position. The normal reaction at the hinge when rod becomes vertical m is ?
​(A) mg/2 (B) 3mg/2 (C) 5mg/2 (D) 2mg

Answer 1

The only forces acting on the rod is the force by weigth

W=Mg

the force acts from the centre of mass

energy=MgL/2

MgL/2=Iω²/2

ω=√3g/L

centripetal force=Mrω²

                             =ML/2*3g/L

                             =3/2*Mg

Normal force =wt+centripetal force

                      = Mg+ 3/2*Mg

                      =5/2*Mg  

Answer 2

Answer:

5mg/2

Explanation:

mg+3mg/2

5mg/2

mass=m