Using Calculus, It Can Be Shown That If a Ball $h = 256 + 16 t - 16 t ^ { 2 }$

Short Answer

Using calculus, it can be shown that if a ball is thrown upward with an initial velocity of 16 ft/s from the top of a building 256 ft high, then its height h above the ground t seconds later will be $h = 256 + 16 t - 16 t ^ { 2 }$
. During what time interval will the ball be at least 64 ft above the ground