Cars A and B are traveling around the circular race track. At the instant shown, A has a speed of 78ft/s and is increasing its speed at the rate of 15 ft / s2, whereas B has a speed of 117ft/s and is decreasing its speed at 25 ft / s2.
Determine the relative acceleration of car A with respect to car B at this instant.
Determine the angle ?a of aA/B (counterclockwise from the positive x axis).