A boy weighs 72 N on the surface of earth. The gravitational force on a body due to earth at a height equal to half the radius of earth will be

Step-by-step solution

At height ( h = R n ) , the value of acceleration due to gravity is given by, g _ h = ( n n +1 )^2 ~g . For n =2 , aligned & g _ h = ( n n +1 )^2 ~g = ( 2 2+1 )^2 ~g = 4 9 ~g & ~W _ h = mg _ h = 4 9 mg = 4 9 72=32 ~N aligned