Total Momentum = Momentum A + Momentum B
The Conservation of Momentum
The total momentum is the same before and after a collision!
Note: The values chosen for these problems are values intended to make the math simple
so that all students can focus on the concepts.
They are not numbers that would realistically reflect a true collision.


Before the collision...

Car A has a mass of 200 kg and is moving right with a speed of 5 m/s.

Car B has a mass of 300 kg and is moving right with a speed of 4 m/s.

After the collision...

Car A is moving to the right with a speed of 2 m/s.

How fast is car B moving?


Before the collision...

Car A has a mass of 100 kg and is moving right with a speed of 8 m/s.

Car B has a mass of 150 kg and is moving right with a speed of 6 m/s.

After the collision...

Car A is moving to the right with a speed of 5 m/s.

How fast is car B moving?


Before the collision...

Car A has a mass of 200 kg and is moving right with a speed of 10 m/s.

Car B has a mass of 400 kg and is moving right with a speed of 5 m/s.

After the collision...

Car A is moving to the right with a speed of 4 m/s.

How fast is car B moving?


Before the collision...

Car A has a mass of 80 kg and is moving right with a speed of 4 m/s.

Car B has a mass of 50 kg and is moving right with a speed of 3 m/s.

After the collision...

Car A is moving to the right at an unknown speed.

Car B is moving to the right with a speed of 5 m/s.

What is the speed of car A after the collision?


Before the collision...

Car A has a mass of 400 kg and is moving right with a speed of 5 m/s.

Car B has a mass of 300 kg and is moving right with a speed of 4 m/s.

After the collision...

Car A is moving to the right at an unknown speed.

Car B is moving to the right with a speed of 6 m/s.

What is the speed of car A after the collision?


Before the collision...

Car A has a mass of 400 kg and is moving right with a speed of 15 m/s.

Car B has a mass of 200 kg and is stationary before the collision.

After the collision...

Car A is stationary.

How fast is car B moving?


Before the collision...

Car A has a mass of 100 kg and is stationary.

Car B has a mass of 300 kg and is moving to the right with a speed of 12 m/s.

After the collision...

Car B is stationary.

How fast is car A moving?


Before the collision...

Car A has a mass of 600 kg and is moving forward at 4 m/s.

Car B has a mass of 200 kg and is moving forward at a rate of only 3 m/s.

After the collision..

Car A is stationary.

How fast is Car B moving?


Before the collision...

Car A has a mass of 1000 kg and is moving at a rate of 20 m/s.

Car B has a mass of 2000 kg and is moving at a rate of 10 m/s.

After the collision..

Car A is stationary.

How fast is Car B moving?


Before the collision...

Car A has a mass of 20 kg and is moving at 10 m/s.

Car B has a mass of 30 kg and is moving at 5 m/s.

After the collision..

Car A is moving at 4 m/s.

How fast is car B moving?


Before the collision...

Car A has a mass of 200 kg and is moving at 9 m/s.

Car B has a mass of 50 kg and is moving at 4 m/s.

After the collision..

How fast is car A moving?

Car B is moving at 12 m/s.


Before the collision...

Car A has a mass of 60 kg and is moving at an unknown speed.

Car B has a mass of 30 kg and is moving at 8 m/s.

After the collision..

Car A is moving at 4 m/s.

Car B is moving at 6 m/s.


Before the collision...

Car A has a mass of 40 kg and is moving at 5 m/s.

Car B has a mass of 30 kg and is moving at an unknown speed.

After the collision..

Car A is moving at 2 m/s.

Car B is moving at 6 m/s.