2.
In order to calculate how many seconds it took, we can use the free fall formula:
[tex]\Delta S=\frac{gt^2}{2}[/tex]Where DeltaS is the displacement, g is gravity and t is the amount of time.
So, using DeltaS = 450 and g = 9.81, we have:
[tex]\begin{gathered} 450=\frac{9.81\cdot t^2}{2} \\ 9.81t^2=900 \\ t^2=\frac{900}{9.81} \\ t^2=91.74312 \\ t=9.578\text{ s} \end{gathered}[/tex]So it took 9.578 seconds for the cellphone to reach the ground.