Acommuting student leaves home and drives to school at an average speed of 39.0 km/h. after 23.0 min he realizes that he has forgotten his homework and returns home to get it at the same average speed. it takes 10.0 min to find the report, after which the trip to school 39.0 km away to the east is resumed at the same speed as before. what is the average speed for the entire trip ? what is the average velocity for the entire trip?

At a certain instant after jumping from the airplane a, a skydiver b is in the position shown and has reached a terminal (constant) speed vb = 52 m/s. the airplane has the same constant speed va = 52 m/s, and after a period of level flight is just beginning to follow the circular path shown of radius ρa = 2330 m. (a) determine the velocity and acceleration of the airplane relative to the skydiver. (b) determine the time rate of change of the speed vr of the airplane and the radius of curvature ρr of its path, both as observed by the nonrotating skydiver.