A person standing close to the edge on top of a 72-foot building throws a ball vertically upward. The
quadratic function h = – 16ť+ 136t + 72 models the ball’s height about the ground, h, in feet, t seconds after it was thrown.
a) What is the maximum height of the ball?
b) How many seconds does it take until the ball hits the ground?


  1. Answer:

    I hope this helps.

    Step-by-step explanation:

    h(t) = -16t2 + 108t + 28




    Maximum height occurs at the vertex of the height-vs.-time parabola, which is at


    t = -108/[2(-16)] sec = ? sec


    Evaluate h(t) at this value of t to get hmax.




    Set h(t) = 0 and solve the quadratic equation for t.  You will get a positive and a negative solution.  Discard the negative solution, since time starts at t = 0.

Leave a Comment