Question

What is the momentum of a 5000 kg train car that is traveling at 15 m/s?

Answer 1

By definition, the momentum is the product of the mass and velocity:

$$p= mv$$

Substituting $m = 5000kg$ and $v = 15m/s$, obtain:

$$p = 5000kg\cdot 15m/s = 75000\space kg\cdot m/s$$

Answer. $75000\space kg\cdot m/s$.