It is my understanding that when two magnets collide without physically touching, kinetic energy is conserved and the "collision" is elastic. My question is, what mechanisms allow for this exchange in kinetic energy?
[Physics] How is kinetic energy transferred between two colliding magnets
collisionelectromagnetismenergy
Related Solutions
When one says that "kinetic energy is conserved in an elastic collision" that means that the total kinetic energy of the system of particles involved in the collision doesn't change. It does not mean that the kinetic energy of each particle is unchanged. For a two particle system, the kinetic energy of each will change, but the sum won't.
Also, your statement about the change in direction of a particle doesn't matter.
$$K = \frac{1}{2}m (\vec{v}\cdot \vec{v})$$ for a single particle
What is the difference that leads to conservation of kinetic energy in elastic collision ?
The difference is only in the properties of the material of a body. If it is elastic (happy ball) it can deform itself (thus absorbing KE) and then recover the original shape, giving back roughly the same amount of KE, which is considered as temporarily stored in the lattices: this question can be of help to you if you want a deeper insight.
You saw this image here: If a body is not elastic (sad ball) the KE will deform the body and this change is irreversible, the KE will be transformed into heat, sound etc. and will not be available anymore as mechanical energy. In this video you can see the enormous difference between a sad and a happy ball of same mass and momentum. If the concept of impulse is not clearly explained there this answer can be of great help
Why is mechanical energy converted as total energy is conserved in inelastic collision?
Kinetic energy is transformed into an exactly equal quantity of other forms of energy in inelastic collisions, therefore the total energy of the system does not change: KE is not conserved whereas momentum is, but energy in general is conserved anyway
Related Question
- [Physics] Why is kinetic energy conserved in elastic collisions and not inelastic collisions
- [Physics] Why isn’t kinetic energy conserved during an elastic collision between two particles
- [Physics] Conservation of kinetic energy in two dimensional elastic collisions
- Newtonian Mechanics – How to Conserve Kinetic Energy in Perfectly Elastic Collisions
- Newtonian Mechanics – Ball Collision in 2D and Conservation of Momentum & Kinetic Energy
Best Answer
The electromagnetic field itself carries energy. Conservation of energy demands that the total energy of the system, which is the sum of the kinetic energies of the magnets and the energy stored in the EM field, remains constant. This is true for any conservative field theory.
As another example, imagine a system of massive particles initially at rest. The particles begin to gravitate toward one another. So a system which initially had no kinetic energy whatsoever suddenly acquires kinetic energy as the particles begin to move. Where did this kinetic energy come from? The gravitational field. The total energy of the system, however, remains constant.
And to answer your question: how is this energy transfered? By interacting with the field. The field influences the particles and the particles influence the field.