Help is needed with physics of billiards

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SUMMARY

The discussion focuses on calculating the velocities of three billiard balls (A, B, and C) arranged in an equilateral triangle after an impulse J is applied to the cue ball. The user seeks to determine the velocities of each ball post-impact, utilizing the relationship between impulse and momentum (J = Δp). The conversation confirms that conservation of energy can be applied to solve for the unknown velocities, despite the challenge of having more unknowns than equations.

PREREQUISITES
  • Understanding of impulse and momentum (J = Δp)
  • Knowledge of conservation of energy principles
  • Familiarity with vector components in physics
  • Basic concepts of collisions in mechanics
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  • Learn how to decompose vectors into components for collision analysis
  • Explore the principles of elastic and inelastic collisions in physics
  • Investigate the mathematical methods for solving systems of equations in mechanics
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Students studying physics, particularly those focusing on mechanics and collision theory, as well as educators seeking to enhance their understanding of impulse and momentum in practical scenarios.

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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.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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