<PRE><B>Question 151517</B>
{{{h(t)=t(64-16t)}}} Start with the given function.



{{{h(t)=64t-16t^2}}} Distribute



{{{h(t)=-16t^2+64t}}} Rearrange the terms



To find the time it takes to reach the max height, use this formula: {{{t=(-b)/(2a)}}}.



{{{t=(-b)/(2a)}}} Start with the given formula.



From {{{h(t)=-16t^2+64t}}}, we can see that {{{a=-16}}}, {{{b=64}}}, and {{{c=0}}}.



{{{t=(-(64))/(2(-16))}}} Plug in {{{a=-16}}} and {{{b=64}}}.



{{{t=(-64)/(-32)}}} Multiply 2 and {{{-16}}} to get {{{-32}}}.



{{{t=2}}} Divide.



-----------------------------------------

Answer:


So it takes 2 seconds for the ball to reach the max height.

</PRE>