Q.
ge and gp denote the acceleration due to gravity on the surface of the earth and another planet whose mass and radius are twice to that of the earth, then :
Acceleration due to gravity is given by g=R2GM
where G is gravitational constant. For earth: ge=Re2GMe For planet: gp=Rp2GMp
Therefore, gpge=GMp/Rp2GMe/Re2
or gpge=MpMe×Re2Rp2 ...(i)
Given, Mp=2Me,Rp=2Re
Putting the values in the Eq. (i), we obtain gpge=2MeMe×Re2(2Re2) =21×14 =2 ∴gp=2ge