NCERT Gist: Force And Pressure | Additional Study Material for UPSC PDF Download

- A push or a pull on an object is called a force.
- The strength of a force is usually expressed by its magnitude.
- The state of motion of an object is described by its speed and the direction of motion.
- The state of rest is considered to be the state of zero speed.
- An object may be at rest or in motion; both are its states of motion.
- The force resulting due to the action of muscles is known as the muscular force.
- The muscular force that enables us to perform all activities involving movement or bending of our body.
- Since muscular force can be applied only when it is in contact with an object, it is also called a contact force.
- The force responsible for changing the state of motion of objects in all these examples is the force of friction.
- The force exerted by a magnet is an example of a non-contact force.
- The force exerted by a charged body on another charged or uncharged body is known as electrostatic force.
- This force comes into play even when the bodies are not in contact.
- The electrostatic force, therefore, is another example of a non-contact force.
- Gravity is not a property of the earth alone.
- In fact, every object in the universe, whether small or large, exerts a force on every other object. This force is known as the gravitational force.
- The force acting on a unit area of a surface is called pressure.