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]
# l! U  r) S$ ]; k: s, J! D/ z$ m
& q# b5 ^2 G" _$ k% S1 s! o[Specify units of 'J', 'kJ', 'MJ' or 'GJ' in your answer.]


1 o" C4 Q0 e, |5 y2 @so far what I have done is used the equation for GPE
  R8 B% O! p) }8 I3 ~which is
U = - (G me m) / r

: ]3 f+ b1 U# e) s9 H. z) Z/ Z+ swhere G is 6.674e-11 Nmkg-2
me is the mass of the planet 5.1e24 kg
% E0 j" N! F# m; ^/ i" l  b7 ]0 t- Vm is the mass of the space ship 5.9e4 kg
( J' ~) Q% ^# g& {  {6 Kr 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

% s7 Q$ O+ u# V1 M
9 y. b# T0 P9 V% T- B' ?& }1 D用这个公式错了么?
还是说只是纯粹的计算出错?

chulinlong

3# Maths
0 l4 Y6 _0 q  K: @

  Y  ^' e; x* f. t7 d- r, ~% z这个公式对的