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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]
! n3 v$ P9 k( k4 `) x( p; O) `3 [, a9 m% F3 Y2 [' U6 }
[Specify units of 'J', 'kJ', 'MJ' or 'GJ' in your answer.]
7 _7 v: r+ N! R( T8 O/ b0 F M, i: r
9 c( `( ?9 E4 k: G) R8 l$ ~4 Kso far what I have done is used the equation for GPE9 S) J2 A0 R X& h+ G) e
which is
4 `' s; C t; F! W' t, g+ T4 M+ } jU = - (G me m) / r) a+ f; _6 |0 Y# H9 l0 `
" E4 U' s3 H( s+ `
where G is 6.674e-11 Nmkg-2
* Z8 B) c2 O& B5 k; `me is the mass of the planet 5.1e24 kg : H! g: d* {+ M
m is the mass of the space ship 5.9e4 kg
2 h M7 @( C# p% C& ~4 Rr 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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狗仔卡
发表于 2009-11-10 21:41
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