Define gravitational potential at a point in space.
TESS is a satellite of mass $360\,\text{kg}$ travelling in a circular orbit around the Earth, as shown in Fig. 1.1. The Earth's radius is $6.4 \times 10^6\,\text{m}$ and the Earth's mass, treated as a point mass at its centre, is $6.0 \times 10^{24}\,\text{kg}$.
TESS takes $13.7\,\text{days}$ to complete one orbit about the Earth. Show that the orbital radius of TESS is $2.4 \times 10^8\,\text{m}$.
Calculate the change in gravitational potential energy between TESS in orbit and TESS on a launch pad on the Earth's surface.
Using the information in (b)(i), calculate the ratio: $\dfrac{\text{gravitational field strength on surface of Earth}}{\text{gravitational field strength at location of TESS in orbit}}$.