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Suppose the mass of the Earth were doubled (Physics 12) 
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#1
Feb1813, 07:25 PM

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1. The problem statement, all variables and given/known data
Suppose the mass of the Earth were doubled , but it kept the same density and spherical shape. How would the weight of objects at the Earh's surface change? 2. Relevant equations Fg=Gm1m2/r^2 3. The attempt at a solution g=G2m/r^2 g=19.59817612 g/g(on earth  9.8) =2 I know this is wrong because the textbook says the answer is 1.26 or 2^1/3. I have no idea how to get this answer. I did find an online solution but they used equations that I have not been taught. Here is a link to the online solution: http://archives.evergreen.edu/webpag...HW/G6solns.pdf If anyone can explain how to get this answer step by step that would be great. 


#2
Feb1813, 10:00 PM

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If you double the mass, but keep the same density, what happens to the radius?



#3
Feb1813, 10:48 PM

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It would increase?



#4
Feb1913, 07:34 AM

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Suppose the mass of the Earth were doubled (Physics 12)
Did you increase the radius in your calculation?



#5
Feb1913, 08:53 AM

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No I didn't. So it would double as well?



#6
Feb1913, 08:56 AM

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Would it?
What is the relationship between mass and volume? volume and radius for a sphere? 


#7
Feb1913, 06:46 PM

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I get it now. My Physics teacher explained it to me after school. Thank you!



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