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