Free-body diagram builder

Every arrow on a free-body diagram is a force, so every label is F with a subscript: F_w, F_N, F_f, F_T, F_push. Add the vectors you need, orient each one, name it, then check.

The 7-step routine

1. Isolate one object and show only forces acting on it.
2. Draw the weight straight down.
3. Contact scan: trace the block’s outline. Anything touching it may exert a force.
4. Add pulls and pushes at their real angles. Ropes pull away from the block.
5. Add a normal force only if a surface touches the block: perpendicular, away from the surface.
6. Add friction only if the problem has it: parallel to the surface, opposing slipping relative to the surface.
7. Check: do the forces match what the block is doing?