Torque

Moment of a couple

T=Fdtorque=force⋅perpendicular distance between couples\begin{align*} T &= Fd \\ \text{torque} &= \text{force} \cdot \text{perpendicular distance between couples} \end{align*}

Unit of TT = N m\mathrm{N\,m}

Always produces rotational effect

Couple

Pair of equal and parallel forces