This PSEB 8th Class Science Notes Chapter 11 Force and Pressure will help you in revision during exams.
PSEB 8th Class Science Notes Chapter 11 Force and Pressure
→ Force is a push or a pull that produces or tends to produce a change in the state of a body.
→ The effect of force depends not only on the magnitude of force but also depends on the area on which it is applied.
→ Force can change the speed, the direction of motion, and the shape of an object,
→ There are various types of forces such as muscular, magnetic, electrostatic, gravitational, and frictional.
→ Force acting per unit area is called pressure.
→ Liquids and gases apply pressure on the surfaces of the container.
→ The atmosphere also exerts pressure, called atmospheric pressure.
→ The pressure exerted by liquids at a given depth is equal in all directions.
→ The pressure of a column of liquid depends on its depth. The more the depth of the liquid column, the more is the pressure.
→ Gases exert pressure in all directions.
→ Force: It is defined as an external cause that changes or tends to change the state of rest or of uniform motion of an object. It is a vector quantity.
→ Resultant Force: When two or more forces act on a body simultaneously, then a single force that produces the same effect as the combined effect of all the forces together, is called resultant force.
→ The force of Friction: The force which opposes the motion of one body over another body in contact with it, is called the force of friction or simply friction.
→ Gravitation: Gravitation is the attraction between any two bodies (particles) in the universe.
→ Weight: The weight of a body is the force with which the body is attracted towards the centre of the earth.
→ Pressure: Force acting per unit area is called pressure.
→ Atmospheric Pressure: Pressure exerted by the atmosphere on all the objects lying on the earth is called atmospheric pressure.