Free Body Diagrams of Mechanism and How it is Useful:
A Free body diagram is a diagram of a link isolated from the mechanism in order to determine the nature of force and moments acting on links.
The free body diagrams are used in:
1. To understand the physical resoning, which in turn detrmine the reactions at supports
2. It indicates the directions and magnitudes kown force which helps in definding the direstions of unknown force.
3. It helps to consider all the forces acting on the body and aiso exclude the force which is not directly applied to the body.
4. It is also used as conceptal devies in order to idenify the internal force developed in the structures
Eg: shearforce, bending moments.