1. Energy
Part 4: Work

2. Work Fake definition: Something that takes physical or mental effort.
REAL definition: A force that causes a change in displacement (Δx) of an object.

3. Work Work is not done unless an object is moved!
If I push a paperclip and it slides across a table, I’ve done work.
If I apply force to a 2,000 kg boulder for 10 minutes and it doesn’t move, I’ve done NO WORK!

4. Work Work is only done if force and displacement are parallel.
Both vectors must be E & W or N & S
If force helps the motion, positive work is done.
If force opposes the motion, negative work is done.

5. Work Work = Force x displacement W = FΔx In units:
Work = Newtons x meters
= (kg·m/s2)(m)
= kg·m2/s2
= Joules

6. If a force of 48 N to the right is applied to an object and it moves 24 m, how much work was done?
Δx = 24 m
W = FΔx
W = (48N)(24m)
W = 1,152 J

7. W = FΔx W/F = Δx 700J/17N = Δx 41.18m = Δx
If 700 J of work is done on an object as a result of 17 N of forcce being applied, how far will the object move?
W = 700 J
F = 17 N
Δx = ?
W = FΔx
W/F = Δx
700J/17N = Δx
41.18m = Δx