The weight of a body on the earth is 400N . Then weight of the body...

The acceleration due to gravity changes with depth from the surface, which is given by

$g ' = g\left(1 - \dfrac{d}{R}\right) . . . ( i )$

The given data is

$W = 400Nd = \dfrac{R}{2}$

Multiplying equation (i) with the mass we get the weight.

$mg ' = mg\left(1 - \dfrac{\dfrac{R}{2}}{R}\right) = mg\left(\dfrac{1}{2}\right) ⇒ W ' = \dfrac{400N}{2} = 200N$