An elastic
collision is an encounter between two bodies in which the total kinetic
energy of the two bodies after the encounter is equal to their total
kinetic energy before the encounter. Elastic collisions occur only if there is
no net conversion of kinetic energy into other forms. This definition applies
to close encounters between a spacecraft and a gravitating body as well as to
actual collisions between individual atoms etc.During the collision of small
objects, kinetic energy is first converted to potential energy associated
with a repulsive force between the particles (when the particles move
against this force, i.e. the angle between the force and the relative velocity
is obtuse), then this potential energy is converted back to kinetic energy
(when the particles move with this force, i.e. the angle between the force and
the relative velocity is acute).The collisionsof atoms are elastic
collisions v
