A ball is thrown in the windA ball of mass $m$ is thrown and experiences a frictional drag force as it moves through a gas or a fluid. The forces acting on this ball are gravity $-mg\hat{z}$ and the drag force. If a wind is blowing, the drag force can be described by, $\vec{F}_{fric} = -a(\vec{v}-\vec{v}_{\text{wind}}) - b(\vec{v}-\vec{v}_{\text{wind}})|(\vec{v}-\vec{v}_{\text{wind}})|,$ where $a$ and $b$ are constants and $\vec{v}_{\text{wind}}$ is the velocity of the wind which can depend on position and time. For low Reynolds number, the linear term $-a(\vec{v}-\vec{v}_{\text{wind}})$ usually dominates whereas for high Reynolds number, the quadratic term $- b(\vec{v}-\vec{v}_{\text{wind}})|(\vec{v}-\vec{v}_{\text{wind}})|$ dominates. $\vec{F}= m\frac{d^2\vec{r}}{dt^2} = -a(\vec{v}-\vec{v}_{\text{wind}}) - b(\vec{v}-\vec{v}_{\text{wind}})|(\vec{v}-\vec{v}_{\text{wind}})|-mg\,\hat{z}$
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