The equation below models the height in feet, h, of a softball t seconds after it is hit by a batter. h= -16t2+105t+3 Why is the height of the ball a function of time? Each value of time is associated with exactly one height. Each height of the ball is associated with exactly one moment in time. There is exactly one time at which the maximum height is attained. There is a maximum and minimum height that the ball can reach.