Question 159583
This is a type of quadratic equation commonly used in physics.

In other words it is the shape of a parabola. It reaches a max and comes back down to the point of origin.When the ball hits the ground x=0 there is no distance traveled
therefore the equation becomes 0=64t-16t2

factor the equation 0=4t(16-t)

the only times where this equation is 0 is when t=0 and when t=16

therefore it takes 16 seconds for the ball to reach the ground.

ground distance=0.