magnitude of the gravitational force between the two bodies is 4.3 × 10^15N, how far apart are Mars and Phobos? The value of the universal gravitational constant is 6.673 × 10^−11N · m^2/kg^2.
Answer in units of m
Answer in units of m
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Fgrav = GmM/r^2
so, r = sqrt(GmM/F)
plug your numbers and you get
r = sqrt(6.673*10^−11 * 6.51*10^23 * 9*10^15 / 4.3*10^15) = 9.53*10^6 meters.
(Pretty close to wikipedia's data, "Phobos orbits about 9,377 km from the center of Mars")
so, r = sqrt(GmM/F)
plug your numbers and you get
r = sqrt(6.673*10^−11 * 6.51*10^23 * 9*10^15 / 4.3*10^15) = 9.53*10^6 meters.
(Pretty close to wikipedia's data, "Phobos orbits about 9,377 km from the center of Mars")