Question

A projectile is thrown upward so that its distance, in feet, above the ground after t seconds is = -16t² + 6081 What is its maximum height?

Answer 1

For the parabola:
h(t) = -at2 + bt, the maximum occurs at -b/2a
For h(t) = -16t2 + 576t that is -576/(-2)(-16), or -576/32, or 18.
The projectile is at its highest point at 18 seconds.