Chapter 8, pg 114(in my copy). The question regarding the collision with the truck and the car. The truck has a mass of 1500kg and is heading east at 20m/s. The car has a mass of 1000kg and is heading north at 10m/s. The book says, using Pythagorean, we obtain a combined momentum of 3.2x10^4 kg*m/s. But how is this? Pythagorean would be (1.0x10^4)^2 + (3.0x10^4)^2, which should come out to be 1.0x10^8 + 9.0x10^8 and end up being 3.0x10^3, if I am correct(which evidentally I'm not). Could someone give me their insight?