Help is needed with physics of billiards

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    Billiards Physics
AI Thread Summary
The discussion centers on calculating the velocities of three billiard balls arranged in an equilateral triangle after an impulse is applied to the cue ball. The user seeks to determine if it's possible to find these velocities using the impulse-momentum theorem and conservation of energy principles. They have identified the relationships between the velocities of the balls and the impulse but are unsure how to proceed with the equations due to having more unknowns than equations. A participant confirms that the user's approach is correct and encourages the use of conservation of energy to solve the problem. The conversation highlights the importance of balancing equations and utilizing given parameters to derive the desired velocities.
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Homework Statement


three billiard balls are arranged in an equilateral triangle formation labeled A, B, and C. the impulse which the cue imparts to the cue ball is a given, J, the angles at which the three balls will travel(depart from the stationary arrangement) can be easily found. i won't get into more details until i see someone has acknowledged this post. my question is, is it possible to find the velocities with which each ball "departs" (for lack of a better word).


Homework Equations



using J = delta p i am able to find that ... (see #3)

The Attempt at a Solution



|(v_A ) ⃑ |=1/m |J ⃑ |-2|(v_C ) ⃑ |cosθ
and
|(v_B ) ⃑ |=|(v_C ) ⃑ |

please NOTE: theta is given (or can be found as mentioned above because of the nature of the arrangement)
 
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How many equations exist, and how many unknowns do you have?
 
breaking up impulse into components on the one side of the equal sign and final momentum into components (the sum of final momentums for each ball.. mv_A + mv_B +mv_C) on the other side of the equal sign will give us 2 equations. there are 3 unknowns. mass, impulse, angle theta are all given. are there any other equations i could use assuming the impact is ideal. can i incorporate conservation if kinetic energy in any way. i don't think so but looking at it i feel that i should be able to find the magnitudes of velocities.
 
balingwhale: Your statements in post 3 are correct. And yes, you can use conservation of energy. Very good. Try it.
 
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