1) A machine is a device that uses energy to perform work, while a simple machine transforms the direction or magnitude of force without consuming energy. 2) Work is defined as the product of the component of force in the direction of displacement and the magnitude of displacement. 3) Work transfers energy - if energy is transferred to a system, work is positive, and if energy is transferred from a system, work is negative.

1. Work and Energy

4. Work

6. Sample Problem 1:

8. Force to Stretch the Spring

9. Work Done on and by any Spring

12. Problem Solving: