1. Section 1 Work
Chapter 5
Objectives
Recognize the difference between the scientific and ordinary definitions of work.
Define work by relating it to force and displacement.
Identify where work is being performed in a variety of situations.
Calculate the net work done when many forces are applied to an object.

2. Chapter 5 Definition of Work
Section 1 Work
Chapter 5
Definition of Work
Work is done on an object when a force causes a displacement of the object.
Work is done only when components of a force are parallel to a displacement.

3. Section 1 Work
Chapter 5
Definition of Work

4. Chapter 5 Definition of Work Section 1 Work
If the angle is zero, the formula for work simplifies to:
The SI unit of Work is the Joule.

5. Sign Conventions for Work
Section 1 Work
Chapter 5
Sign Conventions for Work

6. Sign Conventions for Work
Section 1 Work
Chapter 5
Sign Conventions for Work
If Force and displacement are in the same direction, the Work is Positive.
If Force and displacement are in opposite directions, the Work is Negative.
If Force and displacement are perpendicular, no Work is done.