Question

An object is said to be in complete equilibrium when

• A. There is no net external force acting on the object
• B. The total clockwise moment about any reference point is equal to the total anti-clockwise moment about the same point
• C. The object moves with a constant angular velocity.
• D. The object moves with a constant acceleration

Answer 1

Answer: (A), (B)

The correct options are
A There is no net external force acting on the object
B The total clockwise moment about any reference point is equal to the total anti-clockwise moment about the same point

A body is said to be in complete equilibrium if it is in translational equilibrium as well as rotational equilibrium.

For translational equilibrium, net external force acting on the body must be zero i.e., $F_{\text{net}}=0$
i.e no acceleration
For rotational equilibrium, net external torque i.e ${\tau }_{\text{net}}=0$ about a reference point.
Or, total clockwise moment about any reference point is equal to the total anti-clockwise moment about the same point.

Option (A) and (B) must be true.

An object moving with constant angular velocity may have linear acceleration. So option (C) and (D) are wrong.