A body weighs W0 at Earth’s surface. When it is carried to an altitude of 600km, its weight becomes 0.8125W0. The body is now taken to a certain depth d below the surface where its weight is again 0.8125W0. Take Earth’s radius R=6.4×103km.
Answer the following.
(i) Calculate the value of the depth d.
(ii) Express the depth as a percentage of Earth’s radius.
(iii) Explain in one or two sentences why the required depth is numerically greater than the altitude that produced the same fractional change in weight.