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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]/ N' e! {6 K! H2 R
8 l: E7 o ^3 B
[Specify units of 'J', 'kJ', 'MJ' or 'GJ' in your answer.]+ Q1 u/ a6 S9 u: x
0 k4 O# C' F7 Q7 e& d3 U; Q/ W- m. U& z( i
so far what I have done is used the equation for GPE
4 e% w9 ]/ n$ p( p, o S( d% M0 J% ]which is
, Y6 e$ m% E# p, V/ `, A3 k9 hU = - (G me m) / r! [" O: ^5 L% t |7 e! ?1 L ?
& \1 o% [) m8 t z
where G is 6.674e-11 Nmkg-2" e( y0 K- R( L6 z, x$ k& U
me is the mass of the planet 5.1e24 kg # B) o9 T7 ^$ t3 S( T' S! N
m is the mass of the space ship 5.9e4 kg
0 U; V8 d- m5 W4 v- nr 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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