Lesson: Orbital Speed Physics • 9th Grade

In this lesson, we will learn how to calculate the orbital speed of an object moving along a circular orbit given its orbital radius and the mass of the object it orbits.

Lesson Plan

Students will be able to

know that for an object to move in a circular orbit around a large object of mass at a radial distance , it must have an orbital speed given by ,
calculate , , or using .

Lesson Presentation

Lesson Video

Lesson Explainer

Lesson Playlist

03:02
03:04
+7

03:29

Lesson Worksheet

Q1:

Titan is the largest moon of Saturn. Assuming that Titan follows a circular orbit, with a radius of 1,220,000 km and an orbital speed of 5.57 km/s, calculate the mass of Saturn. Use a value of m³⋅kg⁻¹⋅s⁻² for the universal gravitational constant. Give your answer in scientific notation to two decimal places.

Q2:

A satellite follows a circular orbit around Earth at a radial distance and with an orbital speed . If the satellite were moved closer to Earth, so that it followed a circular orbit with a radius of , at what speed, in terms of , would it have to move in order to maintain its orbit?

Q3:

A satellite follows a circular orbit around Earth at a radial distance and with an orbital speed . At what radius, in terms of , would the satellite have to orbit in order to have an orbital speed of ?