critical calculations. the first was the momentum of each car immediately after the collision. momentum is determined by multiplying each car's speed by its weight. the investigators knew the weights of both cars. by measuring the distance and direction they had slid, their rotation, and the amount of friction, they were able to calculate their post-impact speeds. 30 miles per hour for the sheriff's car, 24 miles per hour for the secret service. next, they looked at the angle at which the two cars had collided. >> the angle of impact in this particular collision evaluation was critical to determining how this collision took place. >> mait calculated that the two cars collided at a ten-degree angle, almost directly head-on. they already knew the direction the sheriff was traveling from the skid marks, so the angle of impact allowed them to calculate