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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]
# [! j4 @3 b8 O0 X {% Y2 N# x' M6 B5 W
[Specify units of 'J', 'kJ', 'MJ' or 'GJ' in your answer.]
: _3 W7 O' O# S) d1 F: y8 K, Z6 }" a4 A# Y* l( l
: k( T4 B4 n) v9 S6 K/ M. Z# f
so far what I have done is used the equation for GPE
5 }- v+ E. V( Q" q: ]* f. X$ F* Wwhich is
; q8 H; R; q/ s. g9 }0 IU = - (G me m) / r4 e. { a/ M4 b7 f6 [# f5 ~1 ^* H
. y' L [" l6 ~! f+ Y
where G is 6.674e-11 Nmkg-2$ A. R: c, t9 V4 w, p0 S/ S! c
me is the mass of the planet 5.1e24 kg
% h7 p( Z) Q# o3 gm is the mass of the space ship 5.9e4 kg : }6 k0 I/ i j: {7 J
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 |
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发表于 2009-11-10 21:41
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