A stone is carried successively to three positions: P at the North Pole, E on the sea-level at the Equator, and C at the centre of the Earth.
(i) Explain qualitatively why the numerical value of acceleration due to gravity is different at P and E.
(ii) Without doing any calculation, state whether the weight of the stone at E will be greater than, less than, or equal to its weight at P. Give two reasons for your answer.
(iii) What would be the weight of the stone at C? Explain clearly.