Question

What are the two main conditions for equilibrium?

Answer 1

The two main conditions for equilibrium are:

1st condition

1. The first condition of equilibrium states that for an object to remain in equilibrium, the net external force acting upon it in all directions must be zero.
2. Any object which is in equilibrium should not experience any linear or angular acceleration. So that the object with constant velocity also have net external force zero.
3. Thus all the forces acting on the object are balanced and are in equilibrium.

2nd condition

1. The second condition of equilibrium states that the net external torque acting on the object must be zero.
2. The axis' position in the reference frame affects torque. However, since rotational and translational equilibrium conditions exist concurrently in one frame of reference, they also hold in any other inertial frame of reference, the net torque about any axis of rotation is still zero.
3. With respect to an inertial frame, an object is said to be in static equilibrium when the object doesn't move or rotates in neither translational nor rotational motion.