if diameter of the earth is doubled ,with mass remaining same ,how will the weight change
if diameter of the earth is doubled ,with mass remaining same ,how will the weight change
@Physics

Question

if diameter of the earth is doubled ,with mass remaining same ,how will the weight change
 if diameter of the earth is doubled ,with mass remaining same ,how will the weight change
 @Physics

agreene · Answer

$$W=mg$$

mass is the same, and none of the bodies that are gravitationaly interacting with the earth are either, so it must weight the same.

anonymous · Answer

weight wil the weight of a body placed on it change
;;

anonymous · Answer

how wil the weight of a body placed on it change

agreene · Answer

What level of physics are you in?

anonymous · Answer

10

agreene · Answer

In that case,

It wont change, because the mass of the earth hasnt changed so it isn't exerting more gravity than the normal earth

anonymous · Answer

but diameter has changed.g decreases with height right??

anonymous · Answer

$$F=G{{m _{1}m _{2}\over {r^2}}}$$

the r increases so the F will decrease

anonymous · Answer

r is distance to the center of the earth

anonymous · Answer

by how much.is it 4 times

anonymous · Answer

diameter is doubled, so r will be 2r and (2r)^2 = 4r
4 is right :)

anonymous · Answer

I should give you a medal for answering your own question and decond-guessing a false answer :)

anonymous · Answer

what  wrong did i say

anonymous · Answer

I mean you identified agreene's answer as false, not your own

anonymous · Answer

k

anonymous · Answer

Yes. The Force is reliant on the square of the distance. As weight is force  then if the masses are the same then the square of two is four.  So if the weight were to remain the same as the diameter of the planet were doubled then the mass would have to increase four-fold.  You can use the equation above to check for yourself (always a good idea to play around with to show yourself the proof of the concepts)

agreene · Answer

This is why I asked her what level of physics, the fact is--she probably hasn't even gotten that far in Newtonian methodology. I'm asuming she only has F=ma to work with, and since the gravitational acceleration will be given as a constant, and mass is constant, force cannot change in that situation. 

Thats not to say that is a true statement, but it is more than likely what she needs.