Question

The weight of the body on the surface of the earth is 392 N . What will be the height of the body on a planet whose mass is double that of the earth and radius is four times that of the earth?

Answer 1

weight on earth(W)= 392N

W=mg=GmMe/Re^2=392N

on a planet A whose mass in 2Me ans radius is 4Re.

W'= Gm2Me/(4Re)^2

=Gm2Me/16Re^2
=GmMe/8Re^2

but GmMe/Re^2=392

so W'=392/8=49N

weight on another planet= 49N

Hope you got it..

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