Elastic Collision

Collision, in simple terms, is when one moving object strikes a stationary body placed in its trajectory. Also, this term applies when two moving objects collide into one another, causing an instance of impact. 

However, if you are wondering what is elastic collision, you have to understand a bit more than simple collision and impact. Elastic collision is an event of a collision between one moving and a stationary body or two objects in motion where the total kinetic energy and momentum remain unaltered. 


What is Elastic Collision? 

A stationary object possesses potential energy, whereas a moving one converts potential energy into kinetic energy when in motion. Besides, momentum refers to motion in a moving body, which you get from the product of mass and velocity. 

Moreover, elastic collision definition states that the overall kinetic energy and the momentum are preserved in case of this category of collision. The concept itself assumes that the colliding objects preserve energy, which hardly happens in real-life events. 

Therefore, elastic collision in physics refers to a standardized and hypothetical situation where the colliding bodies conserve their kinetic energies even after the event of a collision. 


What are the Examples of Elastic Collision? 

Now that you know what elastic collision is, you must move on to a few examples of this phenomenon. It will help you understand the real-life implications of elastic collision and enable you to relate to the events that happen around us. 

Therefore, Elastic Collision Examples are as Follows – 

  • If you drop a ball on the floor, it bounces back towards you instantly. In this event, the ball in motion preserves its overall momentum and kinetic energy, which is why it bounces back. 

  • When two atomic particles collide into each other, they undergo elastic collision. In case there is no loss of energy after contact, you can call it a perfectly elastic collision. 

These instances will certainly help you comprehend and define elastic collision even better. 


What is Inelastic Collision? 

As you have already understood the instances and types of elastic collisions, you must also understand what its counterpart or inelastic collision stands for. 

An inelastic collision is a category of collision among two moving objects, and these objects lose kinetic energy and momentum after contact. For instance, say that you drop a mound of clay on the ground or you witness a car crash. The mound of clay will not bounce back to you, or the car will not continue in its previous trajectory. 

It happens because neither of these objects will be able to preserve its initial kinetic energy and momentum after striking another surface. 


What is the Formula for Elastic Collision?

The elastic collision formula comprises two parts, namely elastic collision formula for kinetic energy and elastic collision for momentum. 

However, Follow the Table Below to Understand What each Component in the Equation Signifies –

  • m1

Mass of body 1

  • m2

Mass of body 2

  • u1

Initial velocity of body 1

  • u2

Initial velocity of body 2

  • v1

Final velocity of body 1

  • v2

Final velocity of body 2


Therefore, the formula for elastic collision kinetic energy is – 

\[\frac{1}{2}\] m1 v12 \[\frac{1}{2}\]  m2 u22 = \[\frac{1}{2}\]  m1 v12 + \[\frac{1}{2}\]  m2 v22

On the other hand, the elastic collision derivation for momentum is – 

m1 u1 + m2 u2 = m1 v1 + m2 v2

A fundamental way to make sure whether a collision is elastic or inelastic is by equating their total kinetic energy. In case it remains the same as before and after the said collision, you can label it as elastic collision. Contrarily, a shift in the total kinetic energy suggests that the category of collision is inelastic. 

However, the energy loss for inelastic collision usually dissipates into sound and heat energy. It helps in maintaining the balance of energy before and after.

Now that you know what is elastic collision, you should go through related topics to understand more about this concept. Besides, you can also download the Vedantu app for an interactive and personalized learning experience.

FAQ (Frequently Asked Questions)

1. What is Elastic Collision?

Ans. The instance of a collision between two objects where the total kinetic energy and momentum remains intact is called elastic collision.

2. What is Elastic Collision Formula for Kinetic Energy?

Ans. The elastic collision formula for kinetic energy is 1/2 m1 v121/2 m2 u22 = 1/2 m1 v12 + 1/2 m2 v22.

3. What is Elastic Collision Formula for Potential Energy?

Ans. The elastic collision formula for potential energy is m1 u1 + m2 u2 = m1 v1 + m2 v2.