### Free-Body Force Diagrams

Free-body diagrams are the simplest way to represent a situation in physics.  Here are a few guidelines to drawing them:

• The object that we're talking about is drawn as a box.
• All forces are drawn as arrows that start at the center of the object.
• Length and direction of the arrow represent size and direction of the force.
• All forces are labeled with their type, and sometimes with their magnitude.

Here are some common abbreviations that people use for the different forces:

• Gravitational force, or weight, is written $F_{g}$
• Normal force is written $F_{n}$
• Tension is written $F_{T}$ , or sometimes just T
• Friction is written $F_{f}$

Watch the following video to see some examples of free-body diagrams:

After you have completed this part of the lesson, you can check the associated box on the main course page to mark it as complete