Free-Body Exercises: Linear Motion In each case the rock is acted on by one or more forces. All drawings are in a vertical plane, and friction is negligible except where noted. Draw accurate free-body diagrams showing all forces acting on the rock. See LM-1. For convenience, you may draw all forces acting at the center of mass, even though friction and normal force act at the point of contact with the surface. Label forces using the following notation from class: F = force of gravity, Fr = tension force, FE = elastic/spring force, FN = normal force, Fy = friction force, Fair = air resistance. LM - 1 Equilibrium LM - 2 Equilibrium LM - 3 Friction prevents sliding FTI FT2 I. Draw arrow 2. Draw the representing tension vectors along the weight. the strings. F=mg The free body diagram is made up only of the three vectors LM - 4 Equilibrium LM - 5 Equilibrium LM - 6 Equilibrium