A LEVEL Gravitational Field Strength

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Imsolost
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#1
Report Thread starter 3 years ago
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Hi! I’m attempting my physics homework at the moment and just flopping shockingly.

The question is:
‘The earth has a mass of 6x10^24kg. Show that the gravitational field strength of the earth is equal and opposite to the gravitational field strength of the sun at the distance of 260000k from the centre of the earth’
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Physics Enemy
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(Original post by Imsolost)
Me = 6*10^24 kg, Ms = 2*10^30 kg, Sep Dist = 1.5*10^11 m. Show |g_e| = |g_s| at 2.6 x 10^8 m from earth.
At point where |g_e| = |g_s|, a test mass has 0 net force, so equate grav forces eitherside:

Me/Xe^2 = Ms/Xs^2 => Xs/Xe = √(Ms/Me) = 577
=> Xe : Xs ~ 1 : 577 => Xe = (1.5*10^11)/578
=> Xe = 2.6*10^8 m (2 s.f)
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MrMOI
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g = GM / r^2

g = (6.67 * 10-11) x (5.97*10^24) / (radius of earth)^2 = 9.84 ~ 9.8 N / Kg

You can find the gravitational field strength of earth using this equation.

Are you sure the question you wrote down is correct, I assume the distance is in km?
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Imsolost
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Woops yep. I meant Km but I’ve got it in the end don’t worry (I think it was 5.9x10^-3)
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