Energy and Momentum – What is it?

Energy and Momentum

Certain concepts of Physics are elementary to understand completely in order to know various other concepts. Topics like energy, momentum, motion, force, acceleration, displacement are some of the important known concepts of fundamental Physics. These concepts lay the foundation for the advance study of science. Energy is the prime idea of most concepts developed today.

Energy is present everywhere in the universe and cannot be destroyed. Energy has many  types and has a wide range of applications. In this article, let us try to understand what kind of energy is momentum. Also, let’s learn what is meant by momentum.

What is Momentum

We know that momentum is not a form of energy. Momentum is the product of the mass and velocity of an object. Momentum has both magnitude and direction and is a vector quantity. Consider the object of mass ‘m’ moving with the velocity ‘v’, then the momentum of the object is given by:


The SI unit of momentum is kilogram meters per second. The momentum of a particle is a measure of the time required for a constant force to bring it to rest. Newton’s second law states that “the rate of change of a body’s momentum is equal to the net force acting on it”. 

Momentum can be defined as “mass in motion”. The momentum of an object and kinetic energy are the sub-concepts of motion. Let’s know how kinetic energy and momentum are interlinked to each other.

Relationship Between Momentum and Kinetic Energy

The energy possessed by an object while moving from one place to another defines the form of energy – Kinetic energy. Kinetic energy is responsible for making the object move from the state of rest to the state of motion.

Consider a body at rest. For the body to move from a state of rest to a state of motion, force must be applied. While moving the body, work is done, and energy is transferred to the mass, and the body gains speed. This energy required to move the body from rest to motion is termed as kinetic energy. Kinetic energy depends on the mass and velocity of the object. Momentum comes into the picture in a moving body. Again the momentum is also dependent on the factors like velocity and mass. From these features, we can clearly say that momentum and kinetic energy are dependent on each other. Kinetic energy is expressed through the formula. 

Kinetic energy = ½ mv^2


m = mass of the body

v = velocity of the object due to change in motion

The SI unit of kinetic energy is Joules.

When the body moves or accelerates, kinetic energy can be clearly witnessed. When an object is in motion, momentum can be seen. Since kinetic energy and momentum is dependent on the mass and velocity. 

Kinetic energy = ½ mv^2


Kinetic energy = ½ m*v*v

Kinetic energy = (m * v) * (½ * v)

Kinetic energy = p * (½ * v)

We can conclude that the kinetic energy is equal to the product of momentum and half its velocity.