The laws relating to the rotation of a body about an axis are analogous to those describing linear motion. The angular displacement (θ) of a body is the angle in radians through which a point or line has been rotated in a specified sense about a specified axis. The angular velocity (ω) is the rate of change of angular displacement with time, i.e. ω = dθ/dt, and the angular acceleration (α) is the rate of change of angular velocity, i.e. α = dω/dt = d2θ/dt2.
The equations of linear motion have analogous rotational equivalents, e.g.: ω2 = ω1 + αt θ = ω1t + αt2/2 ω22 = ω12 + 2θα The counterpart of Newton's second law of motion is T = Iα, where T is the torque causing the angular acceleration and I is the moment of inertia of the rotating body.
ω2 = ω1 + αt
θ = ω1t + αt2/2
ω22 = ω12 + 2θα