Answer
rise=$2.5$ feet
Work Step by Step
We know that the definition of slope is:
$slope=\frac{rise}{run}$
In this case, we have:
$rise=x$
$run=50$
$slope=0.05$
Thus the slope is:
$slope=\frac{x}{50}=0.05$
We solve for the rise, $x$:
$x=0.05*50=2.5$ feet