Conservation of Angular Momentum

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SUMMARY

Angular momentum is conserved about point A during a collision, as established by the equation integral(M,A dt) = H,2A - H,1A, where M,A represents the moment of all forces about point A. The effect of gravity is negligible during the brief duration of the collision, allowing for the assumption that the angular momentum before the impact (H,1A) equals the angular momentum after the impact (H,2A). This principle holds true despite the presence of a weight causing a moment about point A, which is disregarded due to the short time frame of the collision.

PREREQUISITES
  • Understanding of angular momentum and its conservation laws
  • Familiarity with the concepts of moments and forces in physics
  • Knowledge of collision dynamics and their implications
  • Basic grasp of calculus, particularly integrals
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  • Study the principles of angular momentum conservation in various collision scenarios
  • Explore the effects of external forces on angular momentum
  • Learn about the mathematical derivation of angular momentum equations
  • Investigate the role of time duration in collision analysis
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eurekameh
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Why is angular momentum conserved about point A? I know that integral(M,A dt) = H,2A - H,1A, where M,A is the moment of all forces about point A, H,2A is the angular momentum about point A after the impact and H,1A is the angular momentum about point A before the impact. If angular momentum was conserved, it would mean that integral(M,O dt) = 0. In the problem, however, there is a weight that is causing a moment about point A. Why is this ignored?
 
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eurekameh said:
In the problem, however, there is a weight that is causing a moment about point A. Why is this ignored?
They are assuming that the collision takes only a very short time--so any effect of gravity can be ignored during the collision. The angular momentum about A immediately before the collision equals the angular momentum about A immediately after the collision.
 

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