1. Work and Power

2. Work Work happens when a force moves an object over a distance
If the object does not move, no work is done
For work to be done, the direction of the applied force must be the same as the direction of the motion

3. Work You lift a bag of groceries from the trunk of your car
Is work being done?
You are using force to lift
the bag of groceries, and the force is in the direction of the motion

4. Work You carry a bag of groceries from the car to the kitchen
Is work being done?
You are using force to carry
the groceries
Is the force being applied in the direction of the motion?

5. Calculating Work Work = force x distance moved
W=FΔd (on your reference table!)
Units of work are N·m,
Also known as the joule
Abbreviated J
Set up the triangle!

6. Calculating Work
Work
Force
Distance

7. Work Practice
60N of force is used to move an object a distance of 4.0m. How much work has been done on the object?

8. Work Practice
When you pick up your backpack, you do 58J of work to lift it up 1.3m to put it on your back. What is the force on the backpack?

9. Work Practice
A tow truck tows your car 2200m to the nearest service station. If the truck did 2,970,000J of work to tow the car, what was the force on the car?

10. Work Practice
A crane lifts a steel beam with 5200J of work. If the force on the beam is 240N, what is the distance the beam has been lifted?

11. Power

12. The Power Triangle
Work
Power
Time

13. Power Where have you heard of watts before? Electrical energy
Light bulbs
Can you explain why a bulldozer has more power than a person with a shovel?
Work and Power Tune

14. Calculating Power
Espen and Deion push a sofa across a room in 16 seconds using 142J of work. How much power did they use?

15. Calculating Power
KJ uses 72J of work to push a textbook across the table. He uses 432W of power. How long did it take him to move the book?

16. Calculating Power
Aniké and Alanah move the lab table for 3 seconds using 98W of power. How much work did they do?

17. Calculating Power
Brynne throws a 12N softball 4m in 1.8s. How much power has she used on the softball?