If a body is in equilibrium under the action of three non-parallel coplanar forces, the forces must be concurrent, that is, must meet at a single point. Specific examples are provided here to illustrate the validity of this statement by the use of free-body diagrams as well as during the discussion of equilibrium and moments. These cases are usually not presented in contemporary textbooks; hence, it is our intention to provide examples to help in visualizing the concept. A discussion about four coplanar forces is included.

Topics
Rotational dynamics, Free-body diagrams, Educational aids, Educational assessment
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2018
American Association of Physics Teachers
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