IB Physics A.4.1 Torque and Rotational Motion Key Definitions

Angular acceleration is the rate of change of angular velocity.

Angular displacement is the angle through which an object moves on a circular path. It is measured in radians.

Angular velocity ($\omega$) is the rate of change of angular displacement. It is measured in radians per second (rad/s).

Rotational equilibrium is defined as the state of movement where angular acceleration is zero: total torque is zero.

Torque is the rotational equivalent of force. It measures the ability of a force to cause an object to rotate.

An object is in translational equilibrium when the sum of all the external forces acting on the object equals zero.