MHT CET202015 Oct 2020Morning ShiftPhysicsGravitationActual
The acceleration due to gravity on moon is ( 1 6 )^ th times the acceleration due to gravity on earth. If the ratio of the density of earth ' _ e ' to the density of moon _ m ' is 5 3 , then the radius of moon ' Rm ' in terms of the radius of earth 'Re' is
Options
- A( 7 6 ) Re
- B( 3 18 ) Re
- C( 5 18 ) Re
- D( 1 2 3 ) Re
Correct answer
C. ( 5 18 ) Re
Step-by-step solution
g _ m g _ e = 1 6 _ e _ m = 5 3 R _ m R _ e =? g _ m g _ e = M _ m R _ m ² R _ e ² M _ e = 4 3 R _ m ³ _ m R _ m ² R _ e ² 4 3 R _ e ³ _ e = R _ m _ m R _ e _ e = 1 6 R _ m R _ e = 1 6 _ e _ m = 1 6 5 3 = 5 18