Aman is doing push-ups. he has a mass of 68 kg and his center of gravity is located at a horizontal distance of 0.70 m from his palms and 1.00 m from his feet. find the forces exerted by the floor on his palms and feet.

Mass m = 68 kg
center of gravity from his palms x = 0.7 m
center of gravity from his feet x ' = 1 m
forces exerted by the floor on his palms and feet are F and F ' respectively.

with respect to palms :

( F*0 ) - (W * x ) + [ F ' * (x+x') ] = 0

             -mg*0.7 + F ' * 1.7 = 0    where W = weight = mg

F ' * 1.7 = mg * 0.7

          F ' = mg * 0.7 / 1.7

               = 68 *9.8 * ( 0.7 / 1.7 )

               = 274.4 N

with respect to feet :

( F ' * 0 ) -( W* x ' ) + [F * ( x + x') ] = 0

                -mg*1 + [ F * 1.7 ]= 0

                                 F = mg / 1.7

                                    = 392 N

The correct answer is c