The gravitational field strengths at the surfaces of the Earth and the Moon are 9.8 N kg–1 and 1.7 N kg–1 respectively. If the mass of the Earth is 81 × the mass of the Moon, what is the ratio of the radius of the Earth to the radius of the Moon?
The gravitational field strength at the surface of the Earth is 6 times its value at the surface of the Moon. The mean density of the Moon is 0.6 times the mean density of the Earth.
What is the value of the ratio ?
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