Compute each part of given question:
Question: 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.
Part I: What distance, in km, does the car travel?
Part II: What is the magnitude of the car's displacement, in km, from its initial position?
Part III: What is the speed of the car in m/s?
Do not copy and paste from Google, explain your answer clearly.