Acar on a circular track accelerates from rest. the radius of the track is 0.30km and the magnitude of the constant angular acceleration is 4.5x10-3 rads/s squared. find the centripetal acceleration of the car when it has completed half of a lap.

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.