Chapter 4 - Forces and Newton's Laws of Motion - Problems - Page 113: 12

$F_{net}=587.38N$

We are given $a_x=810m/s^2$ and $a_y=1100m/s^2$ The magnitude of $a_{ball}$ is $$a_{ball}=\sqrt{(a_x)^2+(a_y)^2}=1366m/s^2$$ Using Newton's 2nd Law of Motion, we have $$F_{net}=m_{ball}\times a_{ball}=0.43\times1366=587.38N$$