During upward projection the final velocity is zero, and the gravitational acceleration is -10 m/s² (against the gravity). Therefore; using the equation; S = 1/2gt² + ut Where s is the height h, g is gravitational acceleration, and t is the time and u is the initial velocity u, is 16 ft/s. Thus; h= 1/2(-10)t² + 16t We get; h = -5t² + 16t Therefore; the quadratic equation is 5t² - 16t + h =0
