`g_(m) = g_(e) ((M_(s))/(M_(e))) ((R_(e))/(R_(m)))^(2) = g_(e) xx (1)/(4) xx 4 = (4)/(9) g_(e)`
On earth, `upsilon_(e) = sqrt(2G_(e) R_(e))`,
On Mars, `upsilon_(m) = sqrt(2g_(m) R_(m))`
`:. (upsilon_(m))/(upsilon_(e)) = upsilon_(e) xx (sqrt(2))/(3) = (11.2 xx 1.414)/(3)`
`= 5.28 km s^(-1)`