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

Billiard ball collision at right angle

  • Thread starter Brite
  • Start date
1. Homework Statement
Two billiard balls of equal mass move at right angles and meet at the origin of an xy coordinate system. Ball A is moving upward along the y axis at 2.0 m/s and ball B is moving to the right along the x axis with speed 3.7 m/s. After the collision (elastic), ball B is moving along the positive y axis. What is the final direction of ball A and what are their two speeds?


2. Homework Equations
mAvA + mBvB = mav'A + mBv'B
1/2mAvA2 + 1/2mBvB2 = 1/2mAv'A2 + 1/2mBv'B2


3. The Attempt at a Solution
I know that because this is an elastic collision, momentum and kinetic energy are conserved. I think it's just that the two balls start on different axes is what's throwing me off.
 

LowlyPion

Homework Helper
3,079
4
1. Homework Statement
Two billiard balls of equal mass move at right angles and meet at the origin of an xy coordinate system. Ball A is moving upward along the y axis at 2.0 m/s and ball B is moving to the right along the x axis with speed 3.7 m/s. After the collision (elastic), ball B is moving along the positive y axis. What is the final direction of ball A and what are their two speeds?


2. Homework Equations
mAvA + mBvB = mav'A + mBv'B
1/2mAvA2 + 1/2mBvB2 = 1/2mAv'A2 + 1/2mBv'B2


3. The Attempt at a Solution
I know that because this is an elastic collision, momentum and kinetic energy are conserved. I think it's just that the two balls start on different axes is what's throwing me off.
Welcome to PF.

Indeed the 2 dimensions do make a difference. You will want to treat them separately.

Momentum in x is conserved
Momentum in y is conserved
KE is conserved.
 

Related Threads for: Billiard ball collision at right angle

Replies
6
Views
4K
  • Posted
Replies
8
Views
15K
  • Posted
Replies
1
Views
2K
  • Posted
Replies
17
Views
2K
  • Posted
Replies
2
Views
4K

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top