1. What coefficient of friction do cars need on a flat curve? (a) Calculate the centripetal force exerted on a 950 kg car that negotiates a 550 m radius curve at 23.0 m S Enter to 3 significant figures F = N (b) Assuming an unbanked curve, find the minimum static coefficient of friction between the tires and the road, static friction being the reason that keeps the car from slipping (see figure below). Free-body diagram N W Caption: This car on level ground is moving away and turning to the left. The centripetal force causing the car to turn in a circular path is due to friction between the tires and the road. A minimum coefficient of friction is needed, or the car will move in a larger-radius curve and leave the roadway. Enter to 3 significant figures Hs=