What is elastic collistion?

Answer 1

Elastic collision deceleration is the transfer of energy from an accelerated body to another one that results in the deceleration of the first body by some degree. An example might be the elastic collision and deceleration of, say, a neutron in a nuclear reactor. When a fission event occurs, a neutron leaving the scene will be moving like a bullet from a gun. As the neutron doesn't have a charge, it cannot slow by anything other than elastic scattering, a collision with something. It needs to transfer some energy into whatever it hits to slow down. If it slams into the nucleus of, say, an iron atom, that's not so good. (Iron is the major component in steel, which the reactor vessel is made out of.) The iron nucleus is over 50 times as massive, and the neutron can't give it much energy to slow down. That'd be like trying to slow a high speed Golf ball down by having it slam into, say, a Bowling ball. Not the best thing in the west if we want to slow the golf ball down. (We do need to slow the neutron down in the reactor, by the way.) So what can we use to slow down a neutron? Let's see. We need something near its own size. How about a proton? Like the protons in hydrogen nuclei in water molecules? Oooo, snap! We use water as the heat transfer medium in our reactor and it does double duty as the moderator, or "slower-downer" of neutrons. An elastic scattering deceleration event occurs when a neutron slams into a proton. The proton is knocked across the room and the neutron comes away with less energy. The neutron is said to have decelerated in an elastic scattering event. The slowing neutron is moving to a lower energy state. Toward a state of thermal energy. It is being thermalized. It's slowing down in a thermonuclear reactor. As Paul Harvey would say, and now you know the rest of the story....

Answer 2

Elastic collision is a type of collision whereby the total kinetic energy of the various bodies involved in collision after the collision, equals their total kinetic energy right before the collision.