The radius of a planet R1 and satellite revolves round it in a circle of radius R2. The time period of revolution is T.find the acceleration due to the gravitation of the planet at its surface.

Answer 1

mg´=mω²R₂=m4π²R₂/T²,
g´=4π²R₂/T²,
mg´= G•m•M/R₂²,
mg= G•m•M/R₁²,
mg´/mg = G•m•M•R₁²/R₂²•G•m•M,
g´/g =R₁²/R₂²,
g= g´R₂²/R₁²=4π²R₂³/T²•R₁².