Answer
$1.38m$
Work Step by Step
We know that
$v=\frac{p}{m}$
We plug in the known values to obtain:
$v=\frac{0.780}{0.150}=5.20\frac{m}{s}$
Now we can find the required height as follows:
$v^2=v_{\circ}^2-2g(y-y_{\circ})$
This can be rearranged as:
$y_{\circ}=\frac{v^2}{2g}$
We plug in the known values to obtain:
$y_{\circ}=\frac{(5.20)^2}{2(9.81)}=1.38m$
