Two cars are driving towards an intersection from perpendicular directions. The first car's velocity is 222 meters per second and the second car's velocity is 999 meters per second. At a certain instant, the first car is 888 meters from the intersection and the second car is 666 meters from the intersection. What is the rate of change of the distance between the cars at that instant (in meters per second)

Asteel tube (k=50 w/mk) of inner and outer diameter di = 20mm and do=26mm, respectively, is used to transfer heat from hot gases flowing over the tube (h-hot = 200w/m2k) to cold water flowing through the tube (h-cold = 8000 w/m2k). what is the cold-side overall heat transfer coefficient uc? to enhance heat transfer 16 straight fins of rectangular profile are installed longitudinally along the outer surface of the tube. the fins are equally spaced around the circumference of the tube, each having a thickness of 2mm and a length of 15mm. what is the corresponding overall heat transfer coefficient uc? *solve for uc in both cases*