Free body diagram:
Sol.: In a free body diagram, the body is considered by itself and also the effect of the surroundings on the body is shown by forces and moments. Free body diagrams are used to show internal forces and moments by cutting away the unwanted portion of body.
In a free body diagram of the body in which the body under consideration is freed from all contact surface, and all forces acting on it (Reaction) are drawn is called as free body diagram.