Final answer:
The total momentum of a system of two pool balls, each with a momentum of 674.85 kg*m/s, is 1349.7 kg*m/s, demonstrating conservation of momentum in an isolated system.
Step-by-step explanation:
The momentum of a system is the vector sum of the momenta of all the objects in that system. When two pool balls each have a momentum of 674.85 kg*m/s and are part of an isolated system, the total momentum of the system can be found by adding the individual momenta together, assuming they are moving in the same direction. Therefore, the total momentum of the system is 674.85 kg*m/s + 674.85 kg*m/s = 1349.7 kg*m/s. This example shows that in the absence of external forces, momentum is conserved within a system, in accordance with the conservation of momentum principle.