1. A road running north to south crosses a road going east to west at the point P. Car A is driving north along the first road, and car B is driving east along the second road. At a particular time car A is 10 kilometers to the north of P and traveling at 60 km/hr, while car B is 15 kilometers to the east of P and traveling at 95 km/hr. How fast is the distance between the two cars changing?
2. Suppose that fluid is leaking from an overhead pipe and spreading in the shape of a circle on the ground. If the radius of the circle is increasing at a rate of 0.5 feet per minute, how fast is the area of the circle increasing when the radius is 4 feet?
3. Use differentiation to approximate the maximum error in using 5 cm as the radius of a sphere to calculate its volume if the measurement is off by at most 8 mm. Find the approximation of both the relative and percentage error for the volume.