1. Physical Modeling, Fall 20061 WORK Work provides a means of determining the motion of an object when the force applied to it is known as a function of position.

2. Physical Modeling, Fall 20062 Work Energy Theorem W net is the work done by F net the net force acting on a body.

3. Physical Modeling, Fall 20063 Work Energy Theorem (continued)

4. Physical Modeling, Fall 20064 Work Energy Theorem (continued)

5. Physical Modeling, Fall 20065 Work Energy Theorem (concluded) Define Kinetic Energy Then, W net = K f - K i W net =  K

6. Physical Modeling, Fall 20066 WORK - GENERAL DEFINITION

7. Physical Modeling, Fall 20067 CONSERVATIVE FORCES A force is conservative if the work it does on a particle that moves through a closed path is zero, otherwise, the force is nonconservative.

8. Physical Modeling, Fall 20068 CONSERVATIVE FORCES (cont) A force is conservative if the work it does on a particle that moves between two points is the same for all paths connecting those points, otherwise, the force in nonconservative

9. Physical Modeling, Fall 20069 Potential Energy  U = - W c W net =  K If W net = W c Then,  K = -  U  K +  U = 0  (K + U) = 0

10. Physical Modeling, Fall 200610 MECHANICAL ENERGY U + K = E E = Mechanical Energy  E = 0 E i = E f K i + U i = K f + U f

11. Physical Modeling, Fall 200611 Mass and Spring