Collision Processes

If two bodies collide and if they stick together after the collision, we call this an inelastic collision. Both bodies have the same velocity after the collision (both speed and direction is the same). Because they „stick together“ they also move together after the collision. During an inelastic collision a plastic deformation takes place. During this deformation kinetic energy is transformed into warmth (internal energy). For this reason, the sum of kinetic energy of both bodies after the collision is smaller than the sum of kinetic energy before the collision. In other words: kinetic energy durin an inelastic collision is not conserved. Inelastic collision processes can therefore only be described with the help of the law of momentum conservation.
To understand this better you can imagine that you put some plasticine on the front of two toy cars. What will happen if those plasticine-cars collide? Why don't you test it? Do you have some old toy cars and plasticine?