Force and Pressure Class 8 Chapter 11 CBSE Notes, we explain the full topic which help of point that makes easy to revise and learn all the important facts, Class 8 Chapter 11 Notes
Force and Pressure CBSE Notes
1. Force: A push or a pull, that changes or tends to change the state of rest or uniform motion of an object or changes its direction or shape.
2. A force arises due to the interaction between two objects.
3. Force has magnitude as well as direction.
4. A change in the speed of an object or the direction of its motion or both implies a change in its state of motion.
5. Force acting on an object may cause a change in its state of motion or a change in its shape.
6. A force can act on an object with or without being in contact with it.
7. Types of Forces:
8. Contact Forces: The forces act on a body when the source of force is in actual contact with the body.
(i) Muscular Force: The force exerted by the muscles of the body.
(ii) Mechanical Force: The force produced by a machine.
(iii) Frictional Force: The force that opposes the motion of an object.
9. Non-Contact Forces: Forces that do not involve physical contact between two bodies on which they act.
(i) Magnetic Force: A magnet exerts a non-contact force on objects made of iron, steel, cobalt or nickel.
(ii) Electrostatic Force: The force which results due to the repulsion of similar charges or the attraction of opposite charges.
(iii) Gravitational Forces: The force that exists between any two masses because of their mass.
10. Force per unit area is called pressure.
11. Liquids and gases exert pressure on the walls of their containers.
12. The pressure exerted by the air around us is known as atmospheric pressure.