1. Free Body Diagram

2. Used to show all net forces acting on an object What can an object with a net force of zero be doing?

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

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

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

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

7. 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.

8. 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.