= 12-139. A car is traveling along the circular curve of radius r 300 ft. At the instant shown, its angular rate of rotation is 0 = 0.4 rad/s, which is increasing at the rate of = 0.2 rad/s. Determine the magnitudes of the car's velocity and acceleration at this instant. = 0.4 rad/s =0.2 rad/s2 r = 300 ft