Collisions

A collision is any crash or interaction between two or more objects.

What is a collision?

No!
There are two main types of collisions:
Elastic & Inelastic

Are all collisions the same?

These are crashes where the two objects get stuck together.

Since they're stuck together, they move as one, massive object; sharing one change in momentum.

​​Inelastic

These are crashes where the two objects hit each other then separate.

Since they separate, each object experiences their own changes in momentum after the crash.

Elastic

Both cars share a new momentum with their total mass:
p = (m₁ + m₂) * v

Their masses combine.

After Crash

Each object has its own starting momentum. p₁ & p₂

The total momentum before the crash: p₁ + p₂

Before Crash

Each car has its own final momentum: p_1f & p_2f

The total momentum after the crash: p_1f + p_2f

After Crash

Each object has its own initial momentum. p_1i & p_2i

The total momentum before the crash: p_1i + p_2i

Before Crash