1. During a race the dirt bike was observed to leap up off the small hill at A at an angle of 60 from horizontal (Fig. 1). The bike has a speed of 27.3 ft/s immediately before it lands at B (also at an angle of 60 from horizontal). During the motion, the bike experiences only gravitational acceleration. Use A as the origin and set up a fixed coordinate system xy as shown. For point B, answer the following questions: A. Identify ut (tangential unit vector) and u, (normal unit vector) at B. B. How fast does the bike change its speed immediately before it lands at B? C. What is the radius of curvature of the trajectory immediately before it ends at B? y 60 g B x 20 ft-