3. Suppose a ball is thrown straight upward at time t=0 from a point feet above the ground. ( =0 if it starts from the ground.) If the ball’s initial (upward) velocity is feet/sec, then its height y feet above the ground after t seconds is given by the formula: For insistence, if we stand atop a 110-foot-high building and toss a ball upward with an initial velocity of 50 feet per second, then the rock will travel upward for a while and then eventually be pull by gravity down to the ground.