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Doc Al
Aug30-08, 08:08 AM
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Quote Quote by i_island0 View Post
I would further want to comment on the definition of elastic collision.
Elastic collision is one in which translation Kinetic energy is conserved. IF during collision, some portion of energy is converted into vibrational or even rotational KE, then such a collision cannot be called elastic.
I would say that an elastic collision between macroscopic bodies usually means one in which macroscopic kinetic energy is conserved. That includes translational and rotational KE of the bodies as a whole (treating them as rigid bodies or point masses), but excludes anything that implies internal degrees of freedom (like vibrational modes or internal energy).