Suppose a NASCAR race car rounds one end of the Martinsville Speedway. This end of the track is a turn with a radius of approximately 57.0 m. The track is completely flat and the race car is traveling at a constant speed of about 28.5 m/s (64 mph) around the turn. What is the race car’s centripetal acceleration ac? ac = incorrect m/s². Which force is responsible for the centripetal acceleration in this case? Friction, weight, gravity, normal. What is the minimum coefficient of static friction between the race car’s tires and the track necessary to keep the car from skidding into the wall on the outside of the turn? µs, µs = inco