Question

a projectile is thrown upward so that its distance above the ground after t seconds is given by the function h(t)=-16t^2 +704t. After how many seconds does the projectile take to reach its maximum height? please show work

Answer 1

The easiest way in which this question could be answered is to find the x-coordinate of the vertex, which is also the equation of the axis of symmetry:

In this quadratic expression, a = -16 and b = 704.

The equation of the axis of symmetry is thus t = -b / (2a) = -704 / (2*(-16)) = 22.

The max height is attained after 22 sec.