2011-02-26, 06:07 PM
Simple question. Okay, not so simple question.
Both momentum and energy must be conserved. Momentum is mv, and kinetic energy is 1/2 mv^2. Just by looking at this, it's not possible that both of them can be conserved, except at very specific velocities. If both quantities are conserved, how come in a collision, momentum is considered the "more important" quantity? Why can kinetic energy just be assumed to disappear into heat? What mathematical basis is there for such an assumption?
Both momentum and energy must be conserved. Momentum is mv, and kinetic energy is 1/2 mv^2. Just by looking at this, it's not possible that both of them can be conserved, except at very specific velocities. If both quantities are conserved, how come in a collision, momentum is considered the "more important" quantity? Why can kinetic energy just be assumed to disappear into heat? What mathematical basis is there for such an assumption?