A project by some UHart Civil Engineering students requires them to monitor the traffic safety at a busy intersection. They measure(with a precision stopwatch) that exactly three seconds after car

B passes through the intersection traveling south at vg = 55 mph,minivan A passes through at va = 70 mph on the road that runs at an angle 0 = 60° east of north. The speed of each automobile is constant. (a) the relative velocity (in mph) of B with respect to A, (b) the change in position (in ft) of B with respect to A during a 10-s interval, (c) the distance (in ft) between the two automobiles 3 s after A has passed through the intersection.