# Worksheet: Gravitational Potential Energy in Radial Gravitational Fields

In this worksheet, we will practice calculating the kinetic energy, gravitational potential energy, and total energy of objects with orbital trajectories.

**Q2: **

There are two planets in orbit around a star. Both planets have circular orbits. Planet has a speed of , and Planet has a speed of . (Give your answers to these questions as a decimal if necessary.)

What is the ratio of the orbital radii of the two planets, ?

What is the ratio of the orbital periods of the two planets, ?