1. Gravitational Force
1.1. About Gravitational Force
1.1.1. Its a force that pulls the objects towards the Earth.
1.1.2. The greater the force of gravity pulling an object, the heavier the object
1.2. Weight
1.2.1. As weight is a force, it is measured using a spring balance and is measured in Newtons
2. Pressure
2.1. Pressure increases when:
2.1.1. The force increases
2.1.2. The area decreases
2.2. Pressure is the force acting per unit area
2.3. About Pressure
2.3.1. Pressure = Force / Area
2.3.2. SI unit: N/m2 or Pascal (Pa)
2.3.3. Other units: N/cm2
3. Magnetic Force
3.1. About Magnetic Force
3.1.1. A magnet can attract objects such as iron and steel
3.1.2. There are two poles: The North pole and the South pole
3.2. Poles
3.2.1. Unlike poles attract, like poles repel.
4. Effects of force
4.1. Change the speed of a moving object
4.1.1. Sub Idea 1
4.1.2. Sub Idea 2
4.2. Change the shape or size of an object
4.3. Start an object moving or stop a stationary object
4.4. Change the direction of a moving object
5. Frictional Force
5.1. About Frictional Force
5.1.1. It occurs when two moving surfaces are in contect.
5.1.2. Frictions slows down and stops a moving object
5.2. The use of Frictional Force
5.2.1. It holds a nail in a wall, but it wears away materials
5.3. Ways to reduce Friction
5.3.1. Add lubricants
5.3.1.1. Ball Bearings
5.3.1.2. Oil
5.3.1.3. Water