A car has 400 kgm/s worth of momentum and runs into a truck initially at rest. What is the initial momentum of the truck?

0 kgm/s

Explanation:

The momentum is the product of mass (m) and velocity (v).

Initially the velocity of truck is 0 m/s so the product of mass and velocity becomes 0.

It does not matter what is the weight of truck, because the velocity will make the product of m*v = 0

It does not matter what is the momentum of car.