How can a true elasic collision exist?

  • Thread starter Thread starter Daveman20
  • Start date Start date
  • Tags Tags
    Collision
AI Thread Summary
True elastic collisions, where no energy is lost, are primarily observed at the microscopic level, such as with gas atoms, while macroscopic objects like balls cannot achieve this due to thermodynamic properties that produce heat and increase disorder during deformation. The analogy of two wine glasses chiming together is misleading, as any audible collision indicates inelasticity. At the microscopic scale, particles obey conservation laws without energy loss, but when collisions involve larger objects, energy is dissipated as heat. Therefore, while elastic collisions are a useful concept in physics, they are not fully realized in everyday macroscopic interactions. Understanding these distinctions clarifies the nature of collisions across different scales.
Daveman20
Messages
21
Reaction score
0
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
 
Physics news on Phys.org
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
 
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.
 
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
 
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.
 
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.
 
Last edited:
Hi there, im studying nanoscience at the university in Basel. Today I looked at the topic of intertial and non-inertial reference frames and the existence of fictitious forces. I understand that you call forces real in physics if they appear in interplay. Meaning that a force is real when there is the "actio" partner to the "reactio" partner. If this condition is not satisfied the force is not real. I also understand that if you specifically look at non-inertial reference frames you can...
I have recently been really interested in the derivation of Hamiltons Principle. On my research I found that with the term ##m \cdot \frac{d}{dt} (\frac{dr}{dt} \cdot \delta r) = 0## (1) one may derivate ##\delta \int (T - V) dt = 0## (2). The derivation itself I understood quiet good, but what I don't understand is where the equation (1) came from, because in my research it was just given and not derived from anywhere. Does anybody know where (1) comes from or why from it the...
Back
Top