Two people a and b weighting 140lb and 180lb, jump off a floating platform in same diretion with a velocity relative to the platform that is completely horizontal and with magnitude Vo=6ft/s for both a and b. The floating platform weighs 800lb. Assume that a, b and the platform are initially at rest. Neglecting the water resistance to the horizontal motion of the platform, determine the speed of the platform after a and be jump at the same time.