一道天体物理的题,实在想不出来了,(2) The Canadian Space Agency gives you a second assignment.A satellite is in circular orbit around Mercury.It travels at a distance of 124 km above the surface of Mercury and its period of rotation is 1

一道天体物理的题,实在想不出来了,(2) The Canadian Space Agency gives you a second assignment.A satellite is in circular orbit around Mercury.It travels at a distance of 124 km above the surface of Mercury and its period of rotation is 1
一道天体物理的题,实在想不出来了,
(2) The Canadian Space Agency gives you a second assignment.A satellite is in circular orbit around Mercury.It travels at a distance of 124 km above the surface of Mercury and its period of rotation is 1 hour 31.5 minutes.(a) Estimate the Mass of Mercury.State which formula(s) you applied and why.Please use only SI units.(b) Estimate Mercury’s mean density if the radius of the planet is 2440 km.You can assume a spherical planet.(c) Compare your answer to the mean density of Earth.Why is it larger/smaller?

一道天体物理的题,实在想不出来了,(2) The Canadian Space Agency gives you a second assignment.A satellite is in circular orbit around Mercury.It travels at a distance of 124 km above the surface of Mercury and its period of rotation is 1
Oh,I see,It's identical to the earth's calculation but as far as I am concerned,question (b) and (a) should be exchanged both place,which means we should know the radius of Mercury first.
There your answers go:
we assume the mass of satellite is" m "；distance of that satellite above the surface of Mercury is " H" Its Angular velocity is "ω" ,cycle time is T.Mercury 's radius is "R"
According to the Law of universal gravitation:
GmM/(r+H)²=mω²（r+H）=m4π²/T²（r+H）（only reason is that we can hereby put the cycle time in ues)
M =4π²(R+H)³/GT² ≈3.3*10 ^23 kg
the volume of a spherical is 4πR³/3
M=ρv=ρ*4πR³/3
the density ρ=3M/4πR³≈5.430g/cm³=5430kg /m³
the density of the earth is 5518kg/m³,which is a little larger than Mercury's.In addition,the radius of our planet is nearly three times bigger than that of Mercury.So,Mercury's size is about 27 times smaller than our planet.

能不能翻译一下先