1. Chapter 5
Pgs

2. Recognize the difference
between the scientific and
layman 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.

3. Work Work tells us how much a force or combination of
forces changes the energy of a system.
Work is the bridge between force (a vector) and
energy (a scalar).

4. Work (W)
Work is done on an object when a force is applied and the object moves
W = Fd
Unit for work: kg•m2/s2 or Joule (J)
SI System: Joule (N m)
1 Joule of work is done when 1 N acts on a body moving it a distance of 1 meter

5. Work is done only when the components of a force are parallel to a displacement
There is no work done by a force if it does not cause displacement
W = Fd(cosΘ)
Wnet = Fnetd(cosΘ)

6. Work is a scalar quantity
Can be positive or negative
Positive if your applied force and direction of movement are the same
Ex. Pushing a vacuum
Pulling a wagon

7. Negative if your applied force is opposite of the direction of movement
Ex. Pushing against a remote control car that is going forward
Pulling against a remote control car that is going in the opposite direction
Friction does negative work on an object

8. Force Types
Conservative forces – related to potential energy changes and is path independent
Non-conservative forces – not related to potential energy changes and is path dependent

9. How much work is done on a vacuum cleaner pulled 3
How much work is done on a vacuum cleaner pulled 3.0 m by a force of 50.0 N at an angle of 30.0° above the horizontal?