The principle of conservation of momentum:

• momentum before is same as momentum after

• If no net external forces, the total momentum in a system remains unchanged

• the total momentum in a system remains unchanged

• If no net external forces, the total initial momentum in a system is equal to the total final momentum of the system

What are the different types of collisions?

• elastic

• perfectly inelastic

• inelastic

• completely inelastic

In elastic collisions,

• momentum is conserved

• kinetic energy is conserved

• kinetic energy is not conserved

• momentum is not conserved

In inelastic collisions,

• momentum is conserved

• kinetic energy is conserved

• momentum is not conserved

• kinetic energy is not conserved

In perfectly inelastic collisions,

• momentum is conserved

• kinetic energy is conserved

• momentum is not conserved

• kinetic energy is not conserved

• colliding objects stick together

Why are cars made of heavy metal extreriors unsafe compared to those made from fiberglass?

• accidents involving fiberglass cars take longer to complete

• heavy metal cars have a higher momentum change compared to similar firberglass cars of the same masses and moving at the same velocities

• A higher deforming force is experience by occupants of a heavy metal car during an accident

• fiberglass has an added component called Zithropod which offers more safety during accidents