1. Work and Power

3. Work done = Force × distance Work The unit of work is the joule (J).

4. Amy uses 20N of force to push a lawn mower 10 meters
Amy uses 20N of force to push a lawn mower 10 meters. How much work does she do?

5. Energy is the ability to do work The unit of energy is also the joule.

6. Power Power is the rate at which work is done       The unit of power is the watt (W)

8. Lets do an example! The driver of a moving car applied the brakes.
The brakes produced an average stopping force of 8 kN (8000 N) and the car stopped having travelled 20 m after the brakes were applied.
Calculate the work done in stopping the car.

9. Calculate the power of this if it takes 5 seconds for the car to stop

10. A girl of mass 60 kg (weight 600 N) climbed a 6 m high stairs in 15 seconds.
Calculate the work she did and the average power she developed while climbing the stairs.

11. A mouse applied a force of 4Newtons to lift a weight 1meter off the ground.
What is the work done?

12. And the power if it takes the mouse 3 seconds to lift the weight