Forces and Pressure

1. Types of forces

1.1. Gravitational force

1.1.1. It is the force that pulls all objects down to the earth

1.1.2. Measured in weight

1.2. Magnetic force

1.2.1. An attraction between two magnets

1.2.2. A repulsion between two magnets

1.2.3. Also happens between a magnet and a magnetic material

1.3. Frictional force

1.3.1. Friction happens when two surfaces are rubbing against each other.

1.3.2. It opposes motion and slows down movement

1.3.3. It is sometimes useful and sometimes a nuisance.

1.3.4. Ways to reduce friction

1.3.4.1. Ball bearings

1.3.4.2. Lubricants

1.3.5. Causes wear and tear to objects with high amount of frictional force eg.wheels

2. Pressure

2.1. It is the force exerted per unit area.

2.2. Increase when the force increases.

2.3. Increases when the area decreases.

3. Effects of forces

3.1. Causes an object to move

3.2. Causes an object to stop or change speed

3.3. Changes the shape of an object

3.4. Changes the direction of a moving object

4. What is a force?

4.1. Pull or push

4.2. SI unit is Newton(N)

4.3. Measuring tools:Spring balance