Free Body Diagram Free Body Diagram Used to

Free Body Diagram

Free Body Diagram • Used to show all net forces acting on an object • What can an object with a net force of zero be doing?

Example • Draw the free body diagram for a box being acted on by all the following forces: 5 N (W), 3 N(S), 8 N (N), and 7 N(E) • Can it be at rest? • Can it be at a constant speed? • What is it doing?

There are Several Types of Forces that can act on an Object 1) Applied Force (Fa) – force applied on an object by another object or person 2) Gravity (FG)– force of attraction between an object and a large massive body (Earth) - also known as Weight (W)

3) Normal (FN) – support force exerted on an object by a stable surface - perpendicular to surface of contact - equal but opposite to gravity

4) Friction (Ff) – force that opposes motion; acts in a direction opposite of motion 5) Air Resistance (Fair) – type of friction caused by air 6) Tension (FT) – force transmitted through a string rope or cable

Drawing Free Body Diagrams 1) A block rests on the floor. 2) A block hangs from a rope attached to the ceiling. 3) A tractor pulls a loaded wagon with a constant force. Ignore friction. 4) A book falls to the floor. Ignore air resistance.

5) A feather floats to the floor at a constant velocity. Consider air resistance. 6) A car travels at a constant velocity 7) A cart initially moving across the floor slows to a stop.