The nardo ring is a circular test track for cars. it has a circumference of 12.5km. cars travel around the track at a constant speed of 100km/h. a car starts at the easternmost point of the ring and drives for 15 minutes at this speed.
what distance, in km, does the car travel?
what is the magnitude of the car's displacement, in km, from its initial position?
what is the speed of the car in m/s?

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*