1. Draw the free body diagram.

2. See if d is perpendicular with F Yes: just Multiply

No: Make it

3. See if F is passing through the point

Yes: M=0

No: Solve

4. If you can not make perpendicular ( 3D ), use cross product.

Remember:

- Force can rotate around an axis if and only if it is not parallel to it.

- Do not forget to find the Cartesian form of the forces in case of complex , 3D problems.