求 一道物理题 12点前

chulinlong

A space craft of mass 5.9×104 kg is in orbit around a planet of 5.1×1024 kg. If the planet can be assumed to be a uniform sphere of radius 5.4×106 m and the space ship is orbit a height of 6.9×105 m above the surface what is the gravitational potential energy of the ship? [G=6.674×10-11 Nm2kg-2]
- M3 ~/ d6 u' ^
[Specify units of 'J', 'kJ', 'MJ' or 'GJ' in your answer.]
3 Z# R3 R2 S1 ^' _% F* s
3 m! o3 m/ H. ^7 l; |
so far what I have done is used the equation for GPE
9 I! Q* O6 y/ n3 v$ awhich is
5 d& f9 e# I0 D* \# |# ]% _. oU = - (G me m) / r

& l$ o+ D6 s7 f, e6 _where G is 6.674e-11 Nmkg-2
2 q* {2 e1 g7 ^0 C; {me is the mass of the planet 5.1e24 kg
# i8 `# z  [) Y+ g1 Rm is the mass of the space ship 5.9e4 kg
r is (i think) the radius of the planet (5.4e4 m) added to the height of the space ship is above the planet (6.9e5 m) and then divided it into G me m

chulinlong

做出来了 谢谢

Maths

3 ^6 g7 x$ S0 b
* m7 w, ]0 s# x+ t' n用这个公式错了么?
! D7 @  F$ `$ `还是说只是纯粹的计算出错?

chulinlong

3# Maths
: n6 S! A) p8 z7 W; W
* h$ s3 ~# ]' H2 ^2 A1 R! l! E8 p
& J6 K  K- X% Z$ W& E, \! V; m这个公式对的