Force and pressure · बल और दाब
A free Physics lesson for Class 8 children.
A force is a push or a pull. It can move a body, stop it, change its speed, change its direction or change its shape.
When two forces act in the same direction they add up. When they act in opposite directions, the net force is their difference.
Forces act through contact, like muscular force and friction, or from a distance, like magnetic, electrostatic and gravitational force.
Pressure is the force acting on a unit area: pressure = force ÷ area. A sharp knife cuts well because its small area gives a large pressure.
Liquids and gases exert pressure on the walls of their container. Air exerts atmospheric pressure on everything around us.