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]
$ Z1 o" z7 e: d  t
) I& X  z! O3 U2 w2 l5 G[Specify units of 'J', 'kJ', 'MJ' or 'GJ' in your answer.]

$ P: J0 D/ X5 t
so far what I have done is used the equation for GPE
* J% x) p' Y/ y' J" k& S- v$ Gwhich is
U = - (G me m) / r
4 p) Q7 A0 S  ~% l, T" Q8 Z1 b
- q$ j- e* ?2 Bwhere G is 6.674e-11 Nmkg-2
me is the mass of the planet 5.1e24 kg
2 U7 n/ I) v1 @  i' j+ p+ Jm 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

6 e- b- u6 |6 s用这个公式错了么?
' c4 D# l, R: L& ?1 F还是说只是纯粹的计算出错?

chulinlong

3# Maths
0 E- B! R$ i3 i4 q
% W) N4 H5 ^2 ^! F' K. J1 M
+ [' J) i, ^- S% a5 m这个公式对的