What is the gravity of a planet 2 times the radius and 3 times the mass of earth

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what is the gravity of a planet 2 times the radius and 3 times the mass of earth
 

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SammyS
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what is the gravity of a planet 2 times the radius and 3 times the mass of earth
Hello cmbswim89. Welcome to PF !

Do you mean, "What is the acceleration due to gravity on the surface of a planet 2 times the radius and 3 times the mass of earth?"

Show us what you have tried, and where you're stuck so we can help you.
 
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well the problem states a person weighs 540N on earth and asks how much he weighs on a planet 2 times the radius and 3 times the mass. i have tried putting that data into the gravitational force equation but multiplying earths mass by 3 and radius by 2 but i don't get any of the multiple choice questions i have
 
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SammyS
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well the problem states a person weighs 540N on earth and asks how much he weighs on a planet 2 times the radius and 3 times the mass. i have tried putting that data into the gravitational force equation but multiplying earths mass by 3 and radius by 2 but i don't get any of the multiple choice questions i have
What equation are you putting the mass & radius into ?

What do you get?
 
  • #5
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F=G(3(m1))(m2)/2r2 so it looks like that with m1 as earths mass and r as earths radius and i get 793.18N
 
  • #6
SammyS
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F=G(3(m1))(m2)/2r2 so it looks like that with m1 as earths mass and r as earths radius and i get 793.18N

Are you using (2r)2 or 2(r2) in the denominator?
 
  • #7
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sr^2 sorry
 

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