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]

% u9 C& M: O! c) Q5 _[Specify units of 'J', 'kJ', 'MJ' or 'GJ' in your answer.]
' T8 t) G: ?9 ?3 l$ F' |
8 W- E4 Q% p* w2 k+ A9 A- A
5 z/ w: K# [# ?" @& G2 tso far what I have done is used the equation for GPE
1 N# o" t8 r" Q2 b5 mwhich is
U = - (G me m) / r

where G is 6.674e-11 Nmkg-2
# r8 |# U) i: m% B0 f1 N/ qme is the mass of the planet 5.1e24 kg
2 E5 ?3 D  Z2 J4 n: wm 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

用这个公式错了么?
# w5 r+ D2 v6 V5 h还是说只是纯粹的计算出错?

chulinlong

3# Maths
! b1 o9 ^& e) v+ B3 G. \) c2 M$ K3 M
  h* X4 j6 P6 Z3 h3 `  W
) P5 K9 d- p6 V# c# s2 O) s这个公式对的