1. EL Science—Component 5 Physics
Types of forces

2. Learning objectives
Describe a force as a push or pull acting on an object due to an interaction with another force.

3. Forces

4. When we talk about “forces”, will you think of?

6. How about using the word “force” in Science, what would you think of?

7. Let’s begin with this activity on BBC bitesize (click on the picture below)

8. What are forces?
A force can be a push or a pull. For example, when you push open a door you have to apply a force to the door. You also have to apply a force to pull open a drawer.
You cannot see a force but often you can see what it does. Forces can change the speed of something, the direction it is moving in or its shape. For example, an elastic band gets longer if you pull it.

9. There are different types of forces

10. Types of forces
Air resistance

11. Lewis Hamilton, the Formula One racing driver will show us what “air resistance” is (you may stop at 3min:23sec)

12. Air resistance

13. Refer to the previous slide and compare with the figure below, which force is air resistance?

14. Types of forces 2) Contact forces
-acts on a point of an object by direct contact

15. Contact forces—Force A, B & C

16. Forces A, B & C are contact forces because they are touching

17. What should we do when we want to stop a car from moving?

18. Step the brake pedal or gas pedal?

19. We should press the brake pedal

20. What will happen to the temperature of the brakes as the car slows down?
Watch this video (you may see some changes right after the first minute)

21. What happened to the temperature of the brakes as the car slows down?
Ans: the temperature of the brakes get ___________________.