* Momentum is a measure of an object's mass in motion. It's calculated by the formula: Momentum (p) = mass (m) x velocity (v)

* Velocity is a vector quantity, meaning it has both magnitude (speed) and direction.

Since both the car and the train have mass and are traveling with the same velocity (which means they have the same speed and direction), they both possess momentum.

Important Note: Even though they have the same velocity, the car and the train will have different momenta if their masses are different. The train, being much heavier, will have a significantly larger momentum than the car.