The gravitational field strength on the Moon is smaller than that on the Earth. A scientist examines a rock which has been brought back from the Moon. He measures three quantities.
the density of the rock
the mass of the rock
the weight of the rock
Which quantities are the same size on the surface of the Earth and on the surface of the Moon?
1 and 2 only
1 and 3 only
2 and 3 only
1, 2 and 3
