Educator

Collisions, Part 2

• In an elastic collision, mechanical energy is conserved, i.e., no heat is generated. The collision of billiard balls may be taken to be elastic.
• In an elastic collision in one dimension, it is usually the case that the velocities of the objects before collision are known. Conservation of mechanical energy and momentum provide the equations that determine the velocities after collision.
• For collisions in two dimensions, it is important to keep in mind the vectorial nature of the momentum. The x-component of the total momentum before collision is equal to the x-component of the total momentum after collision, and similarly for the y-component.