question_answer 45)

  The weight of an object at the centre of the earth of radius R, is (a) zero                                (b) infinite                           (c) R times the weight at the surface of the earth (d) times the weight at the surface of the earth

Answer:

  (a) The weight of an object, w = mg At the centre of the earth, acceleration due to gravity g is zero. And is given by where h = distance from surface of the earth to centre of the earth and at centre (h = R) i.e.,               g'= 0. So,