# The magnus effect

1. Jan 8, 2005

for a soccer game I'm programming, i want to calculate the position and velocity of the ball. I can get those values when I have constant acceleration, but I don't understand how to add the Magnus force. I have read some articles in the internet, and I found a formula I just can't understand:

$$F_{m}=\frac{2\pi^2 \rho\ \omega vr^4} {2r}$$

is it right? so I could say:

$$F_{m}=\pi^2 \rho\ \omega vr^3$$

But which is the velocity it refers? and, how can I relate it to v(t) and x(t)?

Could somebody explain it to me, and how to calculate position adding the magnus force?