Help is needed with physics of billiards

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    Billiards Physics
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Homework Help Overview

The discussion revolves around the physics of billiards, specifically analyzing the motion of three billiard balls arranged in an equilateral triangle after being struck by a cue ball. The original poster seeks to determine the velocities of the balls after the impact, given the impulse imparted to the cue ball and the angles at which the balls will travel.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • The original poster attempts to relate impulse and momentum to find the velocities of the balls, while questioning the number of equations versus unknowns in their setup. Other participants inquire about the equations available and suggest considering conservation principles.

Discussion Status

Participants are actively exploring the relationships between impulse, momentum, and energy conservation. Some guidance has been offered regarding the use of conservation of energy, but no consensus has been reached on the approach to take.

Contextual Notes

The discussion includes considerations of ideal impacts and the constraints of the problem, such as the given angles and the nature of the impulse. There is an acknowledgment of the need for more equations to solve for the unknown velocities.

balingwhale
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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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