Final answer:
The concept of momentum and its conservation is key to understanding collisions. Newton's second law describes how forces affect motion, and the conservation of momentum applies whenever external forces on a system are absent.
Step-by-step explanation:
In the context of collisions, the concept of momentum is central. Newton's second law of motion is often implicated when discussing the forces involved, as it relates to how a force will affect the motion of an object. In an elastic collision, both momentum and kinetic energy are conserved, meaning that after the collision the total momentum and total internal kinetic energy are the same as before the collision, although they may have been redistributed among the colliding bodies.
In contrast, an inelastic collision will preserve total momentum but not the kinetic energy. In the case of a perfectly inelastic collision, the objects stick together post-collision, moving with a combined mass and a velocity determined by the conservation of momentum.
The principle of conservation of momentum dictates that, as long as no external forces are acting on a system (isolated system), the total momentum before and after the collision must remain constant. This is applicable for all types of two-object collisions, whether elastic or inelastic, and is a powerful concept when analyzing the outcome of collisions such as car crashes or the impact between subatomic particles like quarks.