Gravitational Fields Questions
Q1.
(a) State Newton's law of gravitation.
(2 marks)
(b) In 1798 Cavendish investigated Newton's law by measuring the gravitational force between two unequal uniform lead spheres. The radius of the larger sphere was 100mm and that of the smaller sphere was 25mm.
(i) The mass of the smaller sphere was 0.74 kg. Show that the mass of the larger sphere was about 47 kg.
density of lead = 11.3 × 103 kg m–3
(2 marks)
(ii) Calculate the gravitational force between the spheres when their surfaces were in contact.
(2 marks)
(c) Modifications, such as increasing the size of each sphere to produce a greater force between them, were considered in order to improve the accuracy of Cavendish's experiment.
Describe and explain the effect on the calculations in part (b) of doubling the radius of both spheres.
(4 marks)
(Total 10 marks)
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