8. The 2000 kg cable car shown in the figure below descends a 200-m-high hill. In addition to its brakes, the cable car controls its speed by pulling an 1800 kg counterweight up the other side of the hill. The rolling friction of both the cable car and the counterweight are negligible. 30° 200 m Counterweight 20° a. How much bring force does the cable car need to descend at constant speed? b. One day the brakes fail just as the cable car leaves the top on its downward journey. What is the runaway speed at the bottom of the hill?​