91Ó°ÊÓ

1.The first condition of equilibrium is that the center of mass of the body has zero acceleration if the vector sum of all external forces acting on the body is zero.

2. The second condition of equilibrium is that a rigid body in equilibrium can’t have any tendency to start rotating about any point, so the sum of external torques must be zero about any point.

Consider a rigid object in uniform rotation about a fixed axis.

Since, there is no net torque nor force acting on it, the object rotates uniformly at the equilibrium.

Given that the individual particles have acceleration towards the axis implies that the net force acting on the whole system is zero.

Therefore, a rigid object in uniform rotation about a fixed axis satisfies the first and second conditions of equilibrium.