A gas station stands at the intersection of a north-south road and an east-west road. A police car is traveling toward the gas station from the east, chasing a stolen truck which is traveling south away from the gas station. The speed of the police car is 130 mph at the moment it is 5 miles from the gas station. At the same time, the truck is 12 miles from the gas station going 100 mph. At this time, (a) Is the distance between the car and truck increasing or decreasing? How fast? (Distance is measured along a straight line joining the car and the truck.)
(b) How does your answer change if the truck is going 70 mph instead of 80 mph?