Conveyor Friction 2#

A conveyor belt, angled at $\theta ={params.theta}^{\circ }$, carries packages up an incline. The package aboard it slips and begins moving downwards at a constant speed $v_p=params.v\mathrm{f}\mathrm{t}/\mathrm{s}$ relative to the ground. Given that friction can be found as $F=Cv\mathrm{\_}PC$, where $C$ is a constant $params.C$. $v\mathrm{\_}PC$ is the relative velocity of the package to the conveyor.
The package has a weight of $W=params.W\mathrm{l}\mathrm{b}$.