Question 76827
<pre><font size = 6 color = "darkblue"><b>
a hammer is dropped from a construction 
project 576 ft above the ground. the height 
h(in ft) of the hammer is mideled by the 
position equation {{{h(t)=-16t^2+ 576}}} where t 
is the time in seconds. how long will take 
for the hammer to reach the ground?

Plug in {{{h(t) = 0}}} 
That's because when it hits the ground its 
height above the ground is 0.

{{{h(t) = -16t^2+576}}}

   {{{0 = -16t^2+576}}}

 {{{16t^2 = 576}}}

Divide both sides by 16:

    {{{t^2=36}}}

Take positive square roots of both sides:

     {{{t = 6}}}

Answer: the hammer hits the ground in 6 seconds.

Edwin</pre>