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]

  u2 I# X, B8 ^  \2 A[Specify units of 'J', 'kJ', 'MJ' or 'GJ' in your answer.]
4 i& A/ L/ K, G2 M* Z, D4 ]
4 [! j' L# H9 U" }! K1 b, g$ [1 O
( F; m* C" K( m* G1 y" E) {+ }so far what I have done is used the equation for GPE
which is
U = - (G me m) / r
. t' R0 }( t. p+ u1 n
+ v7 q* d: d+ ]1 u# F9 W* Mwhere G is 6.674e-11 Nmkg-2
2 s2 r# F  ]: q$ H) @4 B8 \) f. Hme is the mass of the planet 5.1e24 kg
m 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

4 U& p. Y7 ?' h, V
用这个公式错了么?
还是说只是纯粹的计算出错?

chulinlong

3# Maths

- O; Q* h& i0 F  x
这个公式对的