The Difference Between Elastic and Inelastic Collisions
Collisions are events where two or more objects interact with each other, transferring energy and momentum. These interactions can be classified into two groups: elastic and inelastic collisions. The main difference between these two types of collisions is how they affect the motion of the objects involved.
Elastic Collisions
In an elastic collision, the total kinetic energy and momentum of the system are conserved. This means that the objects involved in the collision exchange energy and momentum without losing any of it to other forms, such as heat, sound or deformation. The objects retain their original shape and size, and their speeds and direction of motion may change but the total energy and momentum of the system remain constant.
A classic example of an elastic collision is a game of pool. When the cue ball hits a stationary target ball, the energy and momentum are transferred between them, but none of it is lost. The target ball will move away with the same speed and direction as the cue ball hit it, while the cue ball will reverse course with the same speed it had before the hit.
Inelastic Collisions
In an inelastic collision, the objects involved lose some of their kinetic energy and momentum to other forms. This means that the objects may deform, get heated up or make sound during the collision. The total energy and momentum of the system are not conserved, as some energy has been transferred to other forms.
A common example of an inelastic collision is a car crash. When two cars collide, the energy and momentum are transferred between them, but some of it is lost to deformation, noise, and heating up of the car parts. The cars will not remain in their original shape or speed, and some of the energy will have been converted into other forms.
Conclusion
Elastic and inelastic collisions differ in how they affect the motion and energy of the objects involved. Elastic collisions conserve the total kinetic energy and momentum of the system, while inelastic collisions do not. Understanding these differences can help us predict the outcome of collisions and design better systems that rely on them, such as airbags, sports equipment, or chemical reactions.
Table difference between elastic and inelastic collisions
| Properties | Elastic Collisions | Inelastic Collisions |
|---|---|---|
| Definition | In an elastic collision, the total mechanical energy of the system is conserved. | In an inelastic collision, some of the total mechanical energy of the system is lost as heat, sound, or deformation. |
| Kinetic Energy | Kinetic energy is conserved. The sum of the kinetic energies of the objects before the collision is equal to the sum of the kinetic energies of the objects after the collision. | Kinetic energy is not conserved. Some of the kinetic energy is transformed into other forms of energy such as heat, sound, or deformation. |
| Momentum | Momentum is conserved. The total momentum of the system before the collision is equal to the total momentum of the system after the collision. | Momentum is conserved. The total momentum of the system before the collision is equal to the total momentum of the system after the collision. |
| Objects after Collision | In an elastic collision, the objects bounce off each other. They stay separated and do not stick together. | In an inelastic collision, the objects stick together after the collision. They move together as one object. |
| Examples | Billiard balls colliding or a ball bouncing off a wall. | Car crashes or a bullet hitting a target. |