Question

Assuming the earth to be a sphere of uniform mass density, how much would a body weigh halfway down to the centre of the earth if it weighed 250 N on the surface?

Answer 1

Weight of body = 250 N

Now, at a depth d, let acceleration due to gravity be g_d,

g_d = g(1-1/2)

= g/2

New weight = mg_d

= mg/2

= 250N/2

= 125 N.