A racetrack has the shape of an inverted cone, as the drawing shows. On this surface the cars race in circles that are parallel to the ground. For a...

A racetrack has the shape of an inverted cone, as the drawing shows. On this surface the cars race in circles that are parallel to the ground. For a speed of 39.1 m/s, at what value of the distance d should a driver locate his car if he wishes to stay on a circular path without depending on friction?