Answer
$2.87m$
Work Step by Step
According to law of conservation of energy
$K.E_{bottom}+U_{bottom}=K.E_{top}+U_{top}$
$\implies \frac{1}{2}mv_{bottom}^2+0=0+U_{top}$
$\implies \frac{1}{2}mv_{bottom}^2=mgy_{top}$
This simplifies to:
$y_{top}=\frac{v_{bottom}^2}{2g}$
We plug in the known values to obtain:
$y_{top}=\frac{(7.50)^2}{2(9.8)}$
$y_{top}=2.87m$
