1. Force and Pressure 1

2. What are Forces?
A push or pull

3. Examples of Forces
Squeezing
Stretching
Twisting
Folding

4. Effects of Forces Object’s shape changes Object’s size changes
Stationary object moves

5. Effects of Forces Moving object stops
Moving object speeds up or slows down
Direction of an object’s motion changes

6. Weighing scale

7. Tsunami

8. Weight lifting

9. Ultimate frisbee

10. Naruto vs Sasuke

11. Measuring Forces S.I unit of force is newton (N)
Spring balance used to measure the amount of force applied

12. Types of Spring Balance
Extension spring balance
Spring stretches when a pulling force acts on it
Greater force, greater extension
Spring attached to a pointer which indicates the amount of force exerted on the spring

13. Types of Spring Balance
Compression spring balance
Spring compressed when a pushing force acts on it
Greater force, greater compression
Spring attached to a pointer which indicates the amount of force exerted on the spring

14. Forces Around Us
Gravity
Friction
Magnetism

15. Gravity Gravity is the force that attracts objects to the Earth
Mass is a measure of the amount of matter in a body
Weight is a measure of the gravitational force exerted on the object

16. Friction Frictional force acts when one materials rubs against another
Friction is useful in walking and when applying brakes to stop a car
Constant friction leads to wear and tear
Friction produces heat

17. Magnetism
Magnetism is the force exerted by a magnet on magnetic materials such as iron and steel
Every magnet has a North pole and a South pole
Like poles repel
Unlike poles attract

18. What is Pressure? Amount of force acting on a unit area
A sharp object pierces a surface more easily than a blunt object

19. Calculating Pressure
Force
Pressure =
Area

20. Applications of Pressure in Everyday Life
Bulldozer
Can openers
Knife
Plane
Suction cups