Find the percentage change in the weight of a body when it is taken fom equator to poles. the polar radius is 6,357 Km and equatorial radius is 6,378 Km.
Let ‘m’ be the mass of a body.
Mass of earth is, M = 5.9721 × 1024 kg
Radius at equator is, Re = 6378000 m
Radius at pole is, Rp = 6357000 m
At the equator, weight, We = GMm/Re 2
At the pole, weight, Wp = GMm/Rp 2
Change in weight = Wp – We = GMm(1/Rp 2 – 1/Re 2)
So, % change in weight is = (Wp – We)/We × 100 %
= GMm(1/Rp 2 – 1/Re 2)/[GMm/Re 2] × 100 %
= (Re 2)(1/Rp 2 – 1/Re 2) × 100 %
Putting the values we get = 0.66%