A ball is thrown vertically upward, which is the positive direction. A little later it returns to its point of release. The ball is in the air for a total time of 8.16 s. What is its initial velocity? Neglect air resistance.
vo = (y - 0.5*a*t^2)/t
vo = (0 - 0.5(-9.8)8.16^2)/8.16
SO vo = 0.5*9.8*8.16 = 39.984 m/s