...
A free-body diagram is a graphical representation used to analyse the forces exerted on objects by other objects. Below we show the
steps that you need to follow to draw the free-body diagram of a box that you push along a rough surface.
...
Step 6. Label the forces in the diagram. Identify the external object that causes each force and also the object on which the force
is exerted. A good habit is to use clear labels indicating the object outside the system that is exerting the force on the object inside the system. (For In this example, F~YouonBox~FYou on Box, means the force that You exert on the Box).