Inelastic Collisions: Solving m1v1 + m2v2 = m1v1' + m2v2

  • Context: High School 
  • Thread starter Thread starter marshall4
  • Start date Start date
  • Tags Tags
    Collisions Formula
Click For Summary

Discussion Overview

The discussion revolves around the equation for momentum conservation in collisions, specifically addressing its application in both elastic and inelastic collisions. Participants explore the need for calculus in solving for velocities and clarify the meaning of the prime notation in the equation.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants assert that the equation m1v1 + m2v2 = m1v1' + m2v2' represents conservation of momentum and can be solved using simple algebra without calculus.
  • Others clarify that the equation applies to both elastic and inelastic collisions and is valid in relativistic contexts if 'relativistic mass' is considered.
  • One participant questions the meaning of the prime notation, asking what it signifies in the context of the equation.
  • There is a request for clarification on the equation specific to completely inelastic collisions.
  • A participant acknowledges a previous error regarding the equation and provides a corrected version that includes changing masses during collisions.
  • Another participant explains that the prime notation is used to differentiate between initial and final values of velocity.

Areas of Agreement / Disagreement

Participants generally agree on the use of the momentum conservation equation but express differing views on the necessity of calculus and the interpretation of the prime notation. The discussion remains unresolved regarding the specifics of completely inelastic collisions.

Contextual Notes

Some assumptions about the definitions of mass and velocity may not be explicitly stated, and the implications of relativistic effects on mass are not fully explored.

marshall4
Messages
50
Reaction score
0
If i have the equation

m1v1 + m2v2 = m1v1' + m2v2'

would i have to use any calulus to find either velocity of the second object?

What is that the equation for? Is it inelastic collisions?
 
Physics news on Phys.org
Originally posted by marshall4
If i have the equation

m1v1 + m2v2 = m1v1' + m2v2'

would i have to use any calulus to find either velocity of the second object?

What is that the equation for? Is it inelastic collisions?
You don't need calculus. Simple algebra. Just solve for v2.

This is the equation for conservation of momentum. It holds in both elastic and inelastic collisions. It's also valid in relativity if the m's are what some people call 'relativistic mass.' In such cases the m's are conserved. I.e. the sum of the m's before the collision is the sum of the m's after the collision.



Pete
 


Originally posted by pmb
You don't need calculus. Simple algebra. Just solve for v2.

This is the equation for conservation of momentum. It holds in both elastic and inelastic collisions. It's also valid in relativity if the m's are what some people call 'relativistic mass.' In such cases the m's are conserved. I.e. the sum of the m's before the collision is the sum of the m's after the collision.



Pete

Doesn't the ' mean prime?

What is the ' there for?

What is the equation for completely inelastic collisions?
 


Originally posted by marshall4
Doesn't the ' mean prime?

What is the ' there for?

What is the equation for completely inelastic collisions?

Actually I meant to write a quote, i.e. "relativistic mass"

I want to applogize. I made an error in that last post. I made a web page on all of this a few weeks ago. See

www.geocities.com/physics_world/sr/inertial_mass.htm

The equation I posted above should have read

m1v1 + m2v2 = m3v3 + m4v4

This will hold in all collisions both eleastic and inelastic, and in both Newtonian mechanics and relativistic mechanics.

Particle N with mass mN and velocity vN. The mass may change in the collision.

Pete
 
The ' is only there to differeniate the original value from the final value.

Nautica
 

Similar threads

Undergrad Why does the equation for elastic collisions work like this?
  • · Replies 1 ·
Replies
1
Views
1K
High School Which equation should be used to calculate impulse: I=F(t) or I=m1v1-m0v0?
  • · Replies 12 ·
Replies
12
Views
2K
Undergrad Momentum vs kinetic energy help
  • · Replies 16 ·
Replies
16
Views
2K
Inelastic collisions -- how is momentum conserved but not energy?
  • · Replies 5 ·
Replies
5
Views
3K
Sequental elastic and inelastic collisions
  • · Replies 4 ·
Replies
4
Views
2K
Elastic collision of block on block
  • · Replies 4 ·
Replies
4
Views
2K
How do I solve for an elastic collision going up a ramp?
  • · Replies 10 ·
Replies
10
Views
4K
Undergrad Questions about conservation of momentum
  • · Replies 3 ·
Replies
3
Views
2K
How to Calculate Speed of Head of Driver After Collision?
  • · Replies 10 ·
Replies
10
Views
3K
Graduate What is the force of a head on collision between a jeep and a bus?
  • · Replies 10 ·
Replies
10
Views
5K