• Support PF! Buy your school textbooks, materials and every day products Here!

Final velocities from head elastic head on collisions

  • Thread starter henry3369
  • Start date
  • #1
194
0

Homework Statement


Ball A with velocity +3.00 m/s collides with ball B with equal mass traveling at -2.00 m/s. What is the velocity of each ball after the collision.

Homework Equations


Not sure.

The Attempt at a Solution


I know that momentum is conserved because, but solving the conservation of momentum equation yields two unknowns. I also tried impulse-momentum theorem and conservation of kinetic energy, but I'm not sure how that will help. The answer is Ball has velocity -2.00 m/s and ball B has velocity +3.00 m/s. Is there a formula to actually solve for this because they don't give you either of the final velocities.
 

Answers and Replies

  • #2
105
3
How did you use the law of conservation of kinetic energy?
 
  • #3
105
3
If you can put one of the velocities of the balls after the collision in term of the other , you can solve this problem.
And the law of conservation of kinetic energy would help you.
 
  • #4
194
0
If you can put one of the velocities of the balls after the collision in term of the other , you can solve this problem.
And the law of conservation of kinetic energy would help you.
Well in my book they gave me a formula for relative velocity which is V2f-V1f = -(V2i-V1i). And I have the initial velocities and which will leave me with two unknowns still. Do I have to relate this somehow to conservation of kinetic energy and solve simultaneous equations?
 
  • #5
194
0
Ahh I got it. Thank you!
 

Related Threads on Final velocities from head elastic head on collisions

  • Last Post
Replies
7
Views
2K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
1
Views
2K
  • Last Post
Replies
5
Views
993
  • Last Post
Replies
6
Views
10K
  • Last Post
Replies
5
Views
6K
  • Last Post
Replies
12
Views
3K
  • Last Post
Replies
4
Views
4K
Replies
1
Views
1K
Replies
4
Views
2K
Top