# Momentum and kinetic energy

bolbol2054
why although the equations of momentum and kinetic energy of an object contains the same symbols m and v we note in an inelastic collision that momentum unlike the kinetic energy is conserved

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Yuqing
Momentum will always be conserved because of the symmetry regarding Newton III. But kinetic energy does not need to be conserved because it can easily be transformed into heat, sound, deformation, etc. Note that the total energy still is conserved, just not kinetic energy. Moreover, inelastic collisions are defined by us to be a collision which does not conserve kinetic energy much like perfectly inelastic collisions are defined to be a collision where the final two objects "stick" together resulting in the maximum loss in kinetic energy.

Ali Inam
The kinetic energy is converted into other forms of energy. It all starts or ends with the motion of the body.

The momentum, whereas, is always there, before collision, after collision.

bolbol2054
that's now clear thank you