Elastic Collision: Momentum or Energy?

Click For Summary

Discussion Overview

The discussion revolves around the definition of elastic collisions in physics, specifically whether they are characterized by the conservation of energy or momentum. Participants reflect on a lab experience related to this concept, questioning their understanding and the criteria for determining elasticity in collisions.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant questions whether elastic collisions are defined by the conservation of energy or momentum, expressing confusion based on a lab experience.
  • Another participant asserts that elastic collisions are defined by the conservation of kinetic energy, while momentum conservation applies to all types of collisions.
  • A third participant expands on the definition of elastic collisions, stating that both translational and rotational energy must remain unchanged, and challenges the first participant's claim about the lab requirements.
  • A suggestion is made to look into Newton's Law of Restitution for more information on inelastic collisions.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the definition of elastic collisions, with differing views on whether energy or momentum is the defining characteristic. The discussion remains unresolved regarding the criteria for elasticity.

Contextual Notes

There are limitations regarding the assumptions made about the definitions of elastic and inelastic collisions, as well as the specific requirements of the lab exercise that may not have been clearly communicated.

Physics is Phun
Messages
100
Reaction score
0
Is elastic collision defined as a collision where no energy is lost or where no momentum is lost? We had to do a lab in class and one question was whether the collison was elastic. I think we all got it wrong because we sayed it was elastic because momentum was conserved. But we were supposed to check if energy was (apparently it wasn't) conserved. (It seems kind of stupid because nowhere in the lab did we have to find the energy so we would have to find it separately to find whether it was elastic or not.) So is elasticity defined by momentum or energy?
 
Physics news on Phys.org
An elastic collision is one in which the kinetic energy is conserved. Momentum is conserved in any collision, whether elastic or inelastic.
 
An elastic collision is one in which the internal energy of the colliding objects remains unchanged meaning that the translational plus rotational energy of both objects is conserved.

Also, you were in fact asked in the lab to find the energy when the question of whether the collision is elastic was raised. :-)
 
If you want to know more about inelastic collision, I suggest you look up on Newton's Law of Restitution.
 

Similar threads

Undergrad Work Done/Energy Transferred in One Dimensional Collision
  • · Replies 5 ·
Replies
5
Views
2K
High School How to determine applied force when two objects collide? (basic physics engine)
  • · Replies 9 ·
Replies
9
Views
3K
Undergrad An Alternative Approach to Solving Collision Problems
  • · Replies 7 ·
Replies
7
Views
6K
High School Elastic collision - should final velocities be asymmetric?
  • · Replies 17 ·
Replies
17
Views
2K
High School Why is KE not conserved when momentum is?
  • · Replies 53 ·
2
Replies
53
Views
6K
Undergrad Momentum Transfer: Elastic Collision vs Inelastic Collision
  • · Replies 11 ·
Replies
11
Views
4K
Graduate Simulating an elastic bouncy ball
  • · Replies 10 ·
Replies
10
Views
3K
High School Understanding Physics for Coding Collision of 2 Balls
  • · Replies 14 ·
Replies
14
Views
5K
Simulation of Elastic Collisions
  • · Replies 41 ·
2
Replies
41
Views
4K
Graduate Conservation of energy in Gravitation
  • · Replies 4 ·
Replies
4
Views
1K