1. Calculation of pressure
1.1. SI unit
1.1.1. Newton per square metre
1.1.2. Also known as Pascal (Pa)
1.2. Formula
1.2.1. Force divided by area
2. About force
2.1. A push or a pull
2.2. Effects of forces
2.2.1. Change the speed of a moving object, either by increasing its speed or slowing it down
2.2.2. Change the shape or size of an object.
2.2.3. Start an object moving or stop a moving object.
2.2.4. New node
2.3. Measurement of a forces
2.3.1. Forces are measured with force-meters.
2.3.2. There are two types of spring balances – extension spring balances and compression spring balances .
2.3.2.1. Extension spring balance
2.3.2.1.1. The spring stretches when a force pulls on it.
2.3.2.1.2. The greater the force, the more the spring stretches
2.3.2.2. Compression spring balance
2.3.2.2.1. The spring is compressed when a force acts on it
3. Pressure
3.1. What is pressure?
3.1.1. Pressure is an expression of force exerted on a surface per unit area.
3.1.2. Pressure depends on two things – Force and area
3.2. How to increase pressure
3.2.1. We can increase pressure by decreasing the area the pressure is acting on
3.2.1.1. For the same force, when a smaller surface is in contact with an object, the pressure exerted on the object is higher.
4. Force
4.1. Frictional force
4.1.1. Friction is the force that opposes motion between 2 surfaces that are in contact
4.1.2. Friction acts in the direction opposite to motion
4.1.3. The heavier an object, the greater magnitude of force acts on the surface, and hence, the greater the friction
4.1.4. Friction produces heat and causes wear and tear.
4.1.5. Friction provides us with grip
4.2. Gravitational force
4.2.1. Gravity is the force of attraction that exists between objects that have mass
4.2.2. The strength of the pull of gravity between 2 objects depends on their mass and the distance between them.
4.2.3. The greater the mass, the greater the gravitational force.
4.2.4. Please note:
4.2.4.1. Weight is not the same as mass
4.3. Magnetic force
4.3.1. Magnetic force is the force of attraction and repulsion exerted by a magnet
4.3.2. Magnetic force can pass through non-magnetic materials but cannot pass through magnetic material
4.3.3. Like poles repel while unlike poles attract
4.3.4. Magnetic force can act on an object from a distance