(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{3}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{21}^{2}}vec{r}_{12})
(vec{F}_{21}=-Gfrac{m_{1}m_{2}}{r_{12}^{2}}vec{r}_{12})