Explorers on a small airless planet used a spring gun to launch a ball bearing vertically upward from the surface at a launch velocity of 22 m/sec. Because the acceleration of gravity at the planet's surface was g m/sec , the explorers expected the ball bearing to reach a height of s = 221 -(1/2)get m, t sec later. The ball bearing reached its maximum height 40 sec after being launched. What was the value of 9s