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 34. 0 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.

Two technicians are discussing how to test a car's exhaust by holding a small piece of paper within an inch of the tailpipe mouth. technician a says that if the paper is vibrating due to a "puffing" output from the tailpipe, this signals a smoothly running engine. technician b says that if the paper is being drawn toward the tailpipe, this could indicate burned exhaust valves. who is correct? a. technician b b. both technicians a and b c. technician a d. neither technicians a or b