Definition of Force

In Physics, force is either the push or pull on an object that has a mass m, which results in a change in its acceleration. Therefore, what is force can be defined as the product of mass and acceleration.

This is true even for Newton’s second law:

F = m.a


F is the force on an object

m is the mass of an object

a is the acceleration of an object

Force is a vector quantity since it has both, direction as well as magnitude.

Units of Force

The SI unit of force is Newton denoted by N. Dyne, kilogram-force is also known as kilopound, poundal is the other unit of force.

Types of Forces

There are two types of forces and they are:

  • Contact forces
  • Non-contact forces

Contact Forces

Forces that result when two objects interact by coming in contact with each other. Examples of contact forces are frictional forces, air resistance forces, applied forces, tensional force, and normal force.

Non-contact Force

When force is applied without any contact between the objects, it is known as non-contact force. There are four types of non-contact forces:

  • Gravitational force: It’s the gravitational force which is responsible for making all the objects stay grounded. If there is no gravitational force, then all the objects would have been floating mid air.
  • Electromagnetic force: The force which is either attractive or repulsive, acting between two objects is known as electromagnetic force.
  • Strong nuclear force: This is the strongest non-contact force among the four and has the shortest range.
  • Weak nuclear force: This force is stronger than the gravitational force and acts at subatomic levels. Natural radiation that is present in the universe is because of weak nuclear force.

Properties of Force

Following are the properties of force:

  • For force to interact, a minimum of two bodies must be in contact with each other.
  • As force has magnitude as well as direction, force is a vector quantity.
  • Force is not a physical property such as mass or speed but a property where the interaction between two objects takes place.

Interested to learn more about other Physics related concepts such as what is energy, what is the principle of electrostatic precipitator, stay tuned with BYJU’S.