The Conservation of Matter and the Conservation of Momentum are the consequence of the Conservation of Energy.

I am not sure how much of a proof this is; but light energy is involved both in conservation of energy, and in conservation of momentum. A photon has both energy and momentum.

I am not sure how much of a proof this is; but light energy is involved both in conservation of energy, and in conservation of momentum. A photon has both energy and momentum.

I am not sure how much of a proof this is; but light energy is involved both in conservation of energy, and in conservation of momentum. A photon has both energy and momentum.

I am not sure how much of a proof this is; but light energy is involved both in conservation of energy, and in conservation of momentum. A photon has both energy and momentum.

Both conservation laws are applied. The conservation of momentum and conservation of energy.

However, in an inelastic collision, kinetic energy is not conserved. But total energy IS CONSERVED and the principle of conservation of energy does hold.

working models for energy conservation are:- * * * * *

There are no "laws" of conservation of energy, just the law of conservation of energy. The existence of friction doesn't change anything - the law of conservation of energy still holds.