SOLUTION: An object is propelled vertically upward from the top of a 272-foot building. The quadratic function {{{ s(t)=-16t^2+144t+272 }}} models the ball's height above the ground, s(t), i

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Question 301883: An object is propelled vertically upward from the top of a 272-foot building. The quadratic function +s%28t%29=-16t%5E2%2B144t%2B272+ models the ball's height above the ground, s(t), in feet, t seconds after it was thrown. After how many seconds does the object reach its maximum height? Round to the nearest tenth of a second if necessary.
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
+s%28t%29=-16t%5E2%2B144t%2B272+
.
From inspection, we see that the function describes a parabola that opens downwards. As such, finding the axis of symmetry will give us our answer.
.
The axis of symmetry is found by:
x = -b/2a
x = -144/(2*(-16))
x = 144/(2*(16))
x = 72/16
x = 4.5 seconds