Problema Solution
A rock it thrown from the top of a tower that is 500 feet tall. If its height above the ground can be modeled by
h(t)=-16t^2+64t+500 where h is in feet, and t is in seconds.
To the nearest tenth of a second, how long does it take the rock to reach the ground?
Answer provided by our tutors
lets 't' be the time it takes for the rock to reach the ground
when the rock hits the ground the height is equal to 0
h(t)=-16t^2+64t+500 and h(t) = 0
-16t^2+64t+500 = 0
by solving the quadratic equation we find and consider the positive roots only (since the time can not be negative)
t = 7.94 s
click here to see the step by step solution of the quadratic equation