Conservation of energy in elastic collision

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SUMMARY

The discussion centers on the conservation of energy and momentum in elastic collisions, specifically addressing a homework question regarding the energy dynamics of two colliding blocks. The key conclusion is that in an elastic collision, the kinetic energy of the system is conserved, leading to an increase in the kinetic energy of the lighter block (block 2) after the collision. The confusion arises from the interpretation of velocity changes, particularly when block 2's velocity transitions from negative to positive, which affects its kinetic energy calculation.

PREREQUISITES
  • Understanding of elastic collisions in physics
  • Familiarity with the concepts of kinetic energy and momentum
  • Basic knowledge of vector direction in physics
  • Ability to interpret and analyze collision scenarios
NEXT STEPS
  • Study the principles of elastic and inelastic collisions in detail
  • Learn how to calculate kinetic energy before and after collisions
  • Explore the conservation of momentum in multi-object systems
  • Investigate the effects of mass and velocity on collision outcomes
USEFUL FOR

Students studying physics, educators teaching mechanics, and anyone interested in understanding the principles of energy conservation in collisions.

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Homework Statement



http://www.screencast.com/users/ntrinh3/folders/Jing/media/a4165a56-de0d-4a4a-a01e-49242fd505c4
Need help with question 13

Homework Equations



Conservation of energy and momentum occurs in elastic collision

The Attempt at a Solution



Why would the block 2 have an increase in energy? The velocity of block 2 will now be positive instead of negative but velocity is squared anyway.
The computer's answer was A. Increase, but shouldn't it remain the same?
 
Physics news on Phys.org
Imagine the situation here. A much much heavier object slams into an object with comparable (actually, the same!) speeds. What do you expect the smaller object to do?
 

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