Question Number 159118 by physicstutes last updated on 13/Nov/21
$$\mathrm{Let}\:{F}\left({r}\right)\:=\:\begin{cases}{{mkr},\:\:\mathrm{0}\:\leqslant\:{r}\:<\:{R}}\\{\frac{{m}\mathrm{g}{R}^{\mathrm{2}} }{{r}^{\mathrm{2}} },\:{r}\geqslant\:{R}}\end{cases} \\ $$$$\mathrm{find}\:{D}_{{F}} \\ $$