Answer
The center of the ball is $~~0.21~m~~$ above the top of the net.
Work Step by Step
In part (a), we found that the height of the center of the ball when it reaches the net is $1.11~m$
We can find the height above the net:
$\Delta y = (1.11~m)-(0.90~m) = 0.21~m$
The center of the ball is $~~0.21~m~~$ above the top of the net.
