Given that the acceleration of gravity at the surface of Mars is 0.38 of what it is on Earth, and that Mars' radius is 3400 km, determine the mass of Mars.

Question

kmeis002 · Answer

Do you know the equation for local gravitational acceleration?

anonymous · Answer

No not sure, but could it be g= GM/R^2

kmeis002 · Answer

Yes, and we know that g of earth is ~ 9.81, so mars is .38(g_earth). You should now know every thing  except M using that knowledge.

anonymous · Answer

using that above i got a very large number as in: 298430526.3

kmeis002 · Answer

What is the mass refering to? Is it fine to expect a large number for the mass of mars? What units are on this number?

anonymous · Answer

i am assuming so, and kg

anonymous · Answer

9.81=(0.38)M/(3400)^2
Right?

kmeis002 · Answer

Ah, Not quite, G is the gravitational constant, it should be .38*9.81 = GM/(3400)^2. You can look up G.

loser66 · Answer

is it not $$\large g_{mars} = G\frac{m_{mars}}{r_{mars}^2}$$ where $g_{mars}= 0.38 g_{earth}= 0.38 *9.8 = 3.424$ 
so, $$\large m_{mars}= \frac{3.424 * r_{mars}^2}{G}$$

loser66 · Answer

sorry, 3.724 not 3.424

loser66 · Answer

I think I am right , I checked on internet my answer, it's correct XD

anonymous · Answer

i am getting..6.451287277*10^17

loser66 · Answer

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