1. PHYSICS 50: Lecture 6-1 RICHARD CRAIG

2. Today Exam Review Grades New Homework Chapter 6 Work, Energy and Power “Quiz”

3. Exam 1 Grades Average 55 (raw), 76(curved)

4. Homework #5 Read Chapter 6 Exercises and Problems: 6.3, 6.16, 6.23, 6.33, 6.43, 6.85 Due Thursday, 3/6

5. Work, a force through a distance

6. Work done on an object can change its motion and energy.

7. Important Ideas Work Force times Distance (Nm = Joules) Work Energy theorem Work = change in energy Kinetic Energy Energy associated with motion Power Rate of doing work (J/s = Watts)

8. Example: Pushing a block Push a 5kg block horizontally on a frictionless surface for 10m with a force of 10N Work? Speed? Change in Energy? Power?

9. Refer to Figure 6.3. Follow worked Example 6.1. Only the Parallel component of the force does work

10. Stepwise solution of work done by several forces Sum of the work by each force Is equal to the work done by the net force Tractor pulls a load of logs with constant force