Welcome To My School Study
Do You Know
1. Force
A force is simply a push or a pull acting on an object. It can change the shape, position, or motion of the object.
What force can do:
- Start or stop motion
- Change speed (faster or slower)
- Change direction
- Change shape of an object
Types of force:
- Contact force (needs physical touch)
- Non-contact force (acts without touching)
Examples:
- Pushing a door
- Pulling a rope
2. SI Unit of Force – Newton (N)
Force is measured in Newton (N) in the SI system.
Why Newton?
It is named after Sir Isaac Newton, who explained the laws of motion.
Relation with formula:
Force = Mass × Acceleration
This means a force of 1 Newton is applied when 1 kg mass is accelerated at 1 m/s².
Example:
Kicking a football applies force measured in Newtons.
3. Contact Force – Muscular Force
A contact force is a force that acts only when two objects are in physical contact.
Muscular force:
It is produced by the muscles of humans or animals.
Examples of muscular force:
- Lifting a bag
- Pushing a cart
- Writing with a pen
Why correct answer:
Magnetic, electrostatic, and gravitational forces act without contact, but muscular force needs touch.
4. Pressure (Force ÷ Area)
Pressure is defined as the amount of force applied on a unit area.
Formula:
Pressure = Force ÷ Area
Understanding it:
- Same force on a smaller area → more pressure
- Same force on a larger area → less pressure
Examples:
- A sharp knife cuts easily because pressure is high
- High heels exert more pressure than flat shoes
5. Pressure by Liquids and Gases
Liquids and gases apply pressure in all directions, not just in one direction.
Explanation:
Particles in liquids and gases move freely, so they push on all sides of the container.
Examples:
- Water pushes on the walls, bottom, and top of a container
- Air pressure acts in every direction around us
