A ball is thrown into the air from the roof of the building. Its height (in feet) t seconds is given later by h(t)=64+80t-16t^2

Question

For what length of time is the ball above the roof of the building?

Answer 1

h(0) = 64 feet height of roof So, we have to solve inequality h(t ) ≥ 64; 64 + 80t - 16t² ≥ 64. 5t - t² ≥ 0

0 ≤ t ≤ 5