1. Determine the mass of Earth using the magnitude of the gravitational field strength at the surface of the Earth, the distance r between Earth's surface and its centre (6.38 X 106 m), and the universal gravitation constant.
1. Determine the mass of Earth using the magnitude of the gravitational field strength at the surface of the Earth, the distance r between Earth's surface and its centre6.38 X 10m),and the universal gravitation constant