As we have seen, multiple forces can act on an object, from different directions. It is useful to visualise all these forces with a free-body diagram (FBD).

An FBD basically shows us all the forces that are being exerted on an object. For instance, if an object is being pulled on a surface, it experiences Weight \(W\) downwards, Normal Force \(N\) upwards, External Force \(F\) to the right, and Friction \(F_f\) to the left. You can see this represented in the FBD.