1. Work

2. Review a few things first

3. What is work?
Ted Talk 3:22

4. The formula for Work
W = Fd

5. Examples of Work

6. Non - Examples of Work

7. Tricks

10. Example 1: You discover a box of rocks in middle of your room
Example 1: You discover a box of rocks in middle of your room. You apply an effort force of 65N to push them 2 meters so they are against the wall. How much work have you done?
W = Fd
W = 65N x 2m
W = 130 J

11. Example 2: You now have a box of rocks against the wall of your room
Example 2: You now have a box of rocks against the wall of your room. You decide you like them where they originally were and push them back to the middle of the room. Now how much work have you done to push them back?

12. Example 3: The rocks are now in the middle of the room
Example 3: The rocks are now in the middle of the room. You decide to lift them straight up 0.8 m and carry them across 5 meters across the room. Now how much work have you done (lifting and carrying)? The rocks have a mass of 25 kg.

13. Example 4: Who has done more work?
Stephanie pushes a 20 kg box with a net force of 60N. She moves it 30 m across the floor in 5 seconds.
Dustyn pushes a 20 kg box with a net force of 72N. He moves it 25 m across the floor in 4 seconds.
1800 J 360 W
1800 J 450 W