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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]
! D+ x5 S& c, r9 F( R6 _5 f8 T- I4 N; j1 K0 a, C: g
[Specify units of 'J', 'kJ', 'MJ' or 'GJ' in your answer.]
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7 Q: f& j+ O2 U% P' ^$ Z9 {' jso far what I have done is used the equation for GPE
1 M7 G, j1 C+ E* I0 E; ?which is 9 P( a4 S% K* x0 b: K0 f4 |0 d
U = - (G me m) / r( \1 B$ t3 E( m! L7 X% x
! r) B# ~7 R7 i! C Vwhere G is 6.674e-11 Nmkg-2
6 M0 u3 e" I9 [' m. e& r% ime is the mass of the planet 5.1e24 kg
9 O" o; i" i' Y" n) Sm is the mass of the space ship 5.9e4 kg : _/ E! B( T5 x2 _9 V8 _
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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