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]
9 H( Z1 N2 @# j; V- J
/ G0 n8 \  {+ e. S[Specify units of 'J', 'kJ', 'MJ' or 'GJ' in your answer.]


so far what I have done is used the equation for GPE
0 V' e  U! b4 |which is
4 j/ Y4 a8 S/ T% N  b% TU = - (G me m) / r

" H8 A4 i5 R" p/ |. P( ^. C0 J) awhere G is 6.674e-11 Nmkg-2
% ?. i( u1 t0 W  w/ R1 v2 ?1 `me is the mass of the planet 5.1e24 kg
6 l6 F: U2 R2 Dm is the mass of the space ship 5.9e4 kg
7 x/ V% A, p% I+ e8 u8 k: X& Or 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

" p. m! M2 b1 a( I
$ ]0 q) ^$ W% Q9 p" l用这个公式错了么?
6 K8 C3 z/ R# J& B1 ^还是说只是纯粹的计算出错?

chulinlong

3# Maths
& `6 N" S5 R# W9 {, |
$ R: [5 s3 y3 }, Y' ^7 J9 i
+ l1 W+ u3 I0 j/ x这个公式对的