Question

A person on a bridge 125 feet above the ground drops his cell phone ( picture) the height of the falling cell phone is modeled byHeight =-16t^2+8.5t+125Where the height is measured in feet and the time t is measured in seconds How many seconds will it take the cell phone to reach 65 feet above the ground?T=______seconds (round to 3 decimal places)

Answer 1

You have to solve the following equation

$\begin{gathered} 65=-16t^2+8.5t+125 \\ 0=-16t^2+8.5t+60 \end{gathered}$

After you use the quadratic formula you would get

t=2.2

That would be the final answer

t=2.2