Newtons cradle Conservation of Momentum

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SUMMARY

The discussion centers on the conservation of momentum in Newton's Cradle, emphasizing the need for a modified momentum equation that accounts for the initial momentum of the first ball. It highlights the importance of writing the conservation of energy equation alongside momentum to solve for the velocities of both balls after a collision. Additionally, it questions the assumption that the height of the second ball is less than the initial height and suggests converting values to SI units for accurate calculations, specifically noting that potential energy should not be stated as 14700J without proper unit conversion.

PREREQUISITES
  • Understanding of conservation of momentum principles
  • Familiarity with conservation of energy equations
  • Basic algebra for solving equations with two unknowns
  • Knowledge of SI units and their application in physics calculations
NEXT STEPS
  • Study the derivation of the conservation of momentum equation in elastic collisions
  • Learn how to apply conservation of energy in mechanical systems
  • Practice solving equations with multiple unknowns in physics contexts
  • Review the significance of SI units in scientific calculations and conversions
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Physics students, educators, and anyone interested in understanding the mechanics of Newton's Cradle and the principles of momentum and energy conservation.

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You have the general idea but the conservation of momentum equation needs a bit of modification. The momentum before is correct but the momentum after forgets the momentum of the first ball. It might turn out the the momentum of the first ball is 0 after the collision but this should come from the algebra. Also, write out the equation of conservation of energy. Then you have two equations with two unknowns (velocity of ball 1 and velocity of ball 2 both after the collision). Finally, why do you say that the height of the second ball is less than the initial height?

One last thing, it might help to convert your number to SI units for numerical answer e.g. the potential energy isn't actually 14700J
 

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