KE Loss Qs 8: Elastic Collisions Explained

  • Thread starter Thread starter yolo123
  • Start date Start date
  • Tags Tags
    Loss
Click For Summary

Homework Help Overview

The discussion revolves around the concept of kinetic energy (KE) loss during collisions, specifically focusing on elastic and inelastic collisions. Participants are examining scenarios where kinetic energy may or may not be conserved during collisions between bodies of equal mass and opposite velocities.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are questioning the validity of the statements regarding kinetic energy loss in different collision scenarios. There is a focus on the definitions of elastic and inelastic collisions, with some participants providing counterexamples to challenge the original statements.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the question. Some guidance has been offered regarding the nature of kinetic energy in elastic versus inelastic collisions, but there is no explicit consensus on the original question's phrasing or implications.

Contextual Notes

There is uncertainty regarding the exact wording of the original question, particularly whether it states that "all KE is lost" or "all KE can be lost." This ambiguity is influencing the participants' reasoning and counterexamples.

yolo123
Messages
63
Reaction score
0
8. All KE is lost when:
(a) two bodies of equal mass collide,
(b) two bodies of opposite initial velocity collide,
(c) two bodies of equal mass and opposite initial velocity collide,
(d) never.

None of these make sense to me.
(a) Billard balls have elastic collisions.
(b) Billard balls again disprove this...
(c) Billard balls...
(d) ...... Elastic collisions exist.
 
Physics news on Phys.org
Kinetic energy is lost in inelastic collisions. Does that help? Total energy is however conserved.
 
Yes. I don't see how that helps though. My counter-examples still hold true.
 
Your 'counterexample' on part (d) is incorrect; so what if elastic collisions exist? That tells us nothing about a case where *all* KE is lost, which is what the question is about.

As for the question itself, I'm not actually sure! :o. Are you completely sure it was "All KE is lost when" and not "All KE *can* be lost when"? That would make more sense, because in all the examples it can be conserved as well, depending on whether the collision is elastic or not. Or maybe I'm just delirious because it's midnight. Oh well.
 

Similar threads

Collision between snooker balls
  • · Replies 3 ·
Replies
3
Views
970
Solving the Elastric 3-Body Collision Problem
  • · Replies 2 ·
Replies
2
Views
3K
Ambiguous question on momentum and how it works...
  • · Replies 13 ·
Replies
13
Views
1K
Find elastic energy in the compressed spring.
  • · Replies 12 ·
Replies
12
Views
3K
Physics Help with elastic collision
  • · Replies 5 ·
Replies
5
Views
2K
Two Particles Connected by Massless Rod: Dynamics Analysis
  • · Replies 5 ·
Replies
5
Views
2K
Can total KE ever increase for inelastic collisions?
  • · Replies 5 ·
Replies
5
Views
2K
Elastic Collision and Momentum of Ice Skaters
  • · Replies 16 ·
Replies
16
Views
4K
Complex collision with masses and Velcro
  • · Replies 4 ·
Replies
4
Views
2K
Elastic and inelstic collisions conceptual questions.
  • · Replies 6 ·
Replies
6
Views
3K