Question 606570
Liz drops a marble from the top of a cliff 96 feet off the ground. The height
of the marble is described by the quadratic equation h = -16 t square + 96
where h is the height in feet and t is the time in seconds. Find the time t
when the marble hits the ground. Round to the nearest hundredth. 
.
When the marble hits the ground, the height (h) is zero. So, set h to zero and solve for t:
{{{ h = -16t^2 + 96 }}}
{{{ 0 = -16t^2 + 96 }}}
dividing both sides by -16:
{{{ 0 = t^2 - 6 }}}
{{{ 6 = t^2 }}}
{{{ sqrt(6) = t }}}
{{{ t = 2.45 }}} seconds