Four identical lab carts each have a mass of 200 kg. Different masses are added to the carts and the velocities are measured. All carts move to the right.

The question of this statement is Which cart has the greatest momentum?

Answer:

You need more context to drive a definite conclusion and answer.

There are two possible scenaries depending of the context. These are:

1) Scenary 1: If the forces applied to the carts and the time are equal.

In this case, you calculate the momentum for each cart as Δp = Impulse = force * time and so the moments will be the same for all the carts.

2) Scenary 2: if the velocities of all the carts are the same.

In this case, you use momnentum, p, equals the product of mass and velocity.

Therefore, the cart with the greatest velocity will have the greatest momentum.