SOLUTION: If a rock is dropped from a building 576 feet high, then is distance in feet from the ground after "t" seconds is defined by the following equation: f(t)=16t^2+576 how long d

Algebra ->  Systems-of-equations -> SOLUTION: If a rock is dropped from a building 576 feet high, then is distance in feet from the ground after "t" seconds is defined by the following equation: f(t)=16t^2+576 how long d      Log On


   

Question 527731: If a rock is dropped from a building 576 feet high, then is distance in feet from the ground after "t" seconds is defined by the following equation:
f(t)=16t^2+576
how long does it take in seconds for the rock to hit the ground? It hits the ground when f(t)=0

thank you very much
Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
f(t)=-16t^2+576
set f(t) to zero and solve for t:
0=-16t^2+576
-576=-16t^2
36 = t^2
6 seconds = t