## Quick Reference

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/d*t*, and the **angular acceleration** (α) is the rate of change of angular velocity, i.e. α = dω/d*t* = d^{2}θ/d*t*^{2}.

The equations of linear motion have analogous rotational equivalents, e.g.: ω_{2} = ω_{1} + α*t* θ = ω_{1}*t* + α*t*^{2}/2 ω_{2}^{2} = ω_{1}^{2} + 2θα The counterpart of Newton's second law of motion is *T* = *I*α, where *T* is the torque causing the angular acceleration and *I* is the moment of inertia of the rotating body.

ω_{2} = ω_{1} + α*t*

θ = ω_{1}*t* + α*t*^{2}/2

ω_{2}^{2} = ω_{1}^{2} + 2θα

*Subjects:*
Physics.

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