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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]
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/ C6 W" H! u+ h. W: y$ e5 ]" d+ T% I[Specify units of 'J', 'kJ', 'MJ' or 'GJ' in your answer.]7 [2 e" `; ~( x
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" H& n6 ~ A' {2 R" N1 O9 B8 g/ `6 Kso far what I have done is used the equation for GPE; Z9 k% A0 o4 N. p
which is
) ` F0 i: V' n. a6 z! o, a! aU = - (G me m) / r R. A$ u. I- j% K: i
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where G is 6.674e-11 Nmkg-2
2 N+ A" \1 q k4 Dme is the mass of the planet 5.1e24 kg
9 A: J6 ^9 T" D2 X4 Wm is the mass of the space ship 5.9e4 kg
6 q1 e' O7 G) K0 Pr 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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