1. A 240-kg motorcycle and 70-kg rider are travelling on a horizontal road. The air resistance acting on the rider-bike system is 1280 N [backward]. The coefficient of kinetic friction between the road and the bike is 0.60. (a) What force is moving the bike forward? (b) If the bike is travelling at a constant velocity what is the forward force on the bike? (c) If the bike is accelerating at a rate of 2.16 m/s? [forward] what is the forward force on the bike