## Force

• Force is said to be a pull or push.
• Force can be applied by living and non-living things.
• Source of force and object have to interact to apply a force to an object.
• Between the two objects, one applies the force and the other objects receive the force.

## Direction and magnitude of force

• Magnitude of force is the amount of force and measurement of strength.
• The force can be applied to two objects in the same direction and opposite direction.

## Effect of forces

1. State of motion can be changes with the force
• Rest State - Rest state means the object is not moving.
• Motion state – When an object is moving, then it is said to be in motion state. A force can bring an object in motion state from rest state.

Some examples are

• If a tyre by a boy is to be moved then he will have to push it repeatedly.
• In the game of football, the goalkeeper stops the ball reaching the court by applying the force.
1. The shape of an object can be changed with the force.
• Shape of a rubber band can be changed by stretching it in the opposite direction.

## Types of Force

1. Contact Force
• It is necessary for the objects to interact.
• This force keeps working on the point of contact.
• Friction force and muscular force are the two types of contact force.
• Examples are hitting the ball, pushing a car, Kicking a ball, etc.

1. Non-Contacting force
• There is no interaction between the two objects in this force.
• Electrostatic force, Magnetic force and Gravitational force are the examples of non-contact force.
• Example is pulling of an iron nail by a magnet from a distance.

## Pressure

• Pressure is the force put on per unit area of any surface.
• Pressure = Force/Area
• Pressure and Area are indirectly proportional.

## Pressure exerted by Liquid and Gas

• The inner wall of a container which keeps Liquid and gas gets affected by their pressure.
• The balloon gets inflated when the air gets filled due to the pressure.
• Due to the pore in the bottle, the water starts leaking. This happens because Walls of the bottle gets pressure from the water.

### Atmospheric Pressure

• Different types of gases together make our atmosphere. Hence when the pressure is exerted by the gases it gets exerted in the air and then it is called as Atmospheric pressure.
• Due to the effect of atmospheric pressure on a plane the pressed rubber sucker does not come off.

## Recap

• Force is said to be a pull or push.
• Force can be applied by living and non-living things.
• Magnitude of force is the amount of force and measurement of strength.
• Pressure is the force put on per unit area of any surface.
• Pressure = Force/Area
• Different types of gases together make our atmosphere. Hence when the pressure is exerted by the gases it gets exerted in the air and then it is called as Atmospheric pressure.