Why is the collision angle 90 degrees in a 2d collision?

Click For Summary

Homework Help Overview

The discussion revolves around a two-dimensional collision involving two balls of equal weight, where one ball is stationary and the other is moving. The original poster notes that after the collision, the balls part at a 90-degree angle, and they seek an explanation for this phenomenon.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the conservation of momentum and energy in the context of two-dimensional collisions. Some express uncertainty about the relevance of angles in the collision, while others suggest writing out equations for momentum conservation in both x and y directions.

Discussion Status

There is ongoing exploration of the principles of momentum and energy conservation as they relate to the problem. Some participants have offered guidance on relevant topics to study, while others are still seeking clarity on the relationship between the collision angle and the conservation laws.

Contextual Notes

Participants mention a lack of information regarding the angle in their study materials, which may be contributing to their confusion. The original poster expresses frustration over the perceived lack of direct answers in the resources they have reviewed.

SELFMADE
Messages
80
Reaction score
0

Homework Statement



Stationary ball is placed 20 degrees to the right of the moving ball's trajectory. Both balls are of same weight. Collision occurs and balls part at 90 degree angle. We measured it and it was 90 degrees on two occasions.

Explain why it is 90.

Homework Equations



Momentum conservation law?

The Attempt at a Solution



Can't think of any
 
Physics news on Phys.org
It's a collision, so yes use momentum conservation, but remember that this is a two-dimensional collision.. Is there anything else that is conserved? What do you think?
 
Honestly if I knew I wouldn't ask.

Can someone please, at least, tell me what topic to read?
 
Bump, anyone?
 
Read about two-dimensional collisions and momentum conservation. Then read about conservation of energy. Apply these ideas to your problem.
 
I swear to god I read the whole chapter on impulse and momentum on friday night. There was nothing about angle. I know you're not suppose to reveal direct answers but for christs sake, can I get a break?
 
anyone?
 
It's strange that there was nothing about angle in that chapter on momentum. Momentum has to be conserved in both the x and y directions, so write out the equations for those. Energy is also roughly conserved; if it wasn't, the balls would stick together and not part. So you have three equations: two for conservation of momentum and one for conservation of energy. Solve them.
 
momentum has to be conserved in both the x and y directions,

ok i see now
 

Similar threads

Replies
10
Views
3K
  • · Replies 2 ·
Replies
2
Views
3K
Replies
4
Views
3K
  • · Replies 4 ·
Replies
4
Views
3K
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
Replies
4
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 18 ·
Replies
18
Views
3K
  • · Replies 23 ·
Replies
23
Views
3K