How can a true elasic collision exist?

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In summary, the conversation discusses the concept of elastic collisions and whether there can truly be no loss of energy or heat in these types of collisions. The idea of an elastic collision is likened to the electromagnetic force field between atoms and two wine glasses bumping together. However, it is stated that if a collision can be heard, it is considered inelastic. The conversation also touches on the difference between microscopic and macroscopic objects in terms of elastic collisions, with macroscopic objects not truly exhibiting elasticity due to thermodynamic properties.
  • #1
Daveman20
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Is this something I just have to accept? How can there be no loss of energy/heat when I've always been taught otherwise. I imagine an elastic collision to be like the electromagnetic force field around an atom that just chimes when it hits another spherical force field around a different atom, like two wine glasses bumping together. Is this a good way to imagine it? Thanks in advance
 
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  • #2
There can't (although something like steel balls at normal lab speeds are pretty close)
It's just one of those things like massless springs and friction free slopes that make it possible to see the main points
 
  • #3
mgb_phys said:
There can't (although something like steel balls at normal lab speeds are pretty close)
It's just one of those things like massless springs and friction free slopes that make it possible to see the main points

Thank you, mgb, my intuition remains undefeated! Wikipedia almost had me convinced otherwise.
 
  • #4
Daveman20 said:
I imagine an elastic collision to be like the electromagnetic force field around an atom that just chimes when it hits another spherical force field around a different atom, like two wine glasses bumping together.
If you can hear the collision, it is inelastic.

Bob S
 
  • #5
Microscopic particles like gas atoms collide elastically.If the energy of collision becomes equal to or greater than an excitation or ionisation energy the collisions can become inelastic.
 
  • #6
Microscopic particles (like atoms or electrons) can easily collide elastically. This is a well known type of collision in nuclear physics. This is just a reflection that the particles must obey conservation of momentum and energy directly, with no "coefficient of restitution" or anything like that.

If you're talking about macroscopic objects like balls, then elasticity is a thermodynamic property. In other words, any time you cause deformation in a macroscopic material, you have some kind of thermodynamic material property which causes a correlated production of heat and increases disorder among the molecules in the material. These byproducts like heat take away energy from the momentum. So, along these lines, you never have true elasticity in macroscopic objects.
 
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FAQ: How can a true elasic collision exist?

How is a true elastic collision defined?

A true elastic collision is defined as a collision between two objects where kinetic energy is conserved. This means that the total kinetic energy of the objects before the collision is equal to the total kinetic energy after the collision.

Can a true elastic collision exist in real life?

Yes, it is possible for a true elastic collision to exist in real life. However, in most cases, there will be some loss of kinetic energy due to external factors such as friction and air resistance. For a true elastic collision to occur, the objects must be perfectly elastic and there can be no external forces acting on them.

What factors affect the elasticity of a collision?

The elasticity of a collision depends on the material properties of the objects involved. Objects made of materials with high elasticity, such as rubber, will experience a more elastic collision compared to objects made of materials with lower elasticity, such as metal. The velocity and angle of collision also play a role in the elasticity of a collision.

Can a true elastic collision occur between objects of different masses?

Yes, a true elastic collision can occur between objects of different masses. In this case, the less massive object will experience a greater change in velocity compared to the more massive object. This is because the total momentum of the system must be conserved in a collision.

How is the coefficient of restitution related to a true elastic collision?

The coefficient of restitution is a measure of the elasticity of a collision. It is defined as the ratio of the relative velocity after the collision to the relative velocity before the collision. In a true elastic collision, the coefficient of restitution will be equal to 1, indicating that there is no loss of kinetic energy and the collision is perfectly elastic.

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