Use the height formula.
hf=hi+vo*t-1/2 g t^2 solve for t, you knw hf=hi=0
Will tosses a ball straight upward. Show that if the ball is tossed upward at 18m/s it will be in the air for less than 4s.
2 answers
is there another formula that can be used? I haven't learned that one. Can it be the initial velocity/2