When two objects collide and some of the energy is converted to heat does that mean some of the momentum is lost?

Question
I just read that in an impact some energy can be turned into heat instead of transferring momentum. So how fast would the ice cube impact need to be for them to turn into water? Also what is the best material for turning kinetic into thermal energy?
Update: ignore the bit about ice cubes. there was some sort of glitch on yahoo from my other question?
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General Physics RvTDLR 2 years 1 Answer 1012 views 0

Answer ( 1 )

1. Momentum and kinetic energy are entirely different things.
Momentum is a product of the mass and velocity of an object and Kinetic Energy is the energy which a moving body possesses.
When two objects collide, their kinetic energy (being vibrations of atomic particles) oscillates through each of the objects and exits the objects (usually via a gaseous medium) in the form of thermal or sound energy. This is known as an inelastic collision (as kinetic energy is not conserved). However, if the same collision were to occur in a vacuum, the collision would be elastic (for the kinetic energy could not oscillate into another medium in another form of energy)- which means kinetic energy will be conserved.
Momentum is not converted into energy for it is just the magnitude of the motion which a moving body possesses. Momentum is always conserved- (however, when considering newtonian mechanics and the acting sub-systems, aswell as any acting external forces, momentum can be arguably not conserved).
In conclusion:
Kinetic energy is the energy which is converted into other forms of energy.
I suggest reading up on thermodynamics (and newtonian mechanics, if you want to know more about momentum).