Question

a uniform rod of mass M and length L is made to stand vertically on one and the potential energy of the rod in this position is

Answer 1

THE POTENTTIAL ENERGY =WORK DONE IN RISING IT FROM HORIZONTAL POSTION TO VERTICAL POSTION.

DOING THIS,THE MID POINT OF THE ROD IS RAISED THROUGH A HEIGHT H=L/2.SINCE THE ENTIRE MASS OF THE ROD CAN BE ASSUMED TO BE CONCENTRATED AT MIDPOINT(CENTER OF GRAVITY),

WD=MGH=MGL/2

THEREFORE

PE=MGL/2