772 views

### What speed do satellites orbit at?

The key point to recognise here is that an object undergoing a circular orbit around the Earth is undergoing circular motion. Circular motion is caused by a centripetal force (acting towards the centre of the circle), described by:

F= msatellitev2/r   (eq 1)

In the case of an orbit, the force acting towards the centre is due to the gravity of the Earth, which is described by Newton's law of universal gravitation:

F= GmEarthmSatellite/r2  (eq 2)

We can now equate these two expressions:

Fc = Fg => msatellitev2/r = GmEarthmSatellite/r2  (eq 3)

Now me can rearrange to make v the subject of the equation:

v = sqrt(GmEarth/r)   (eq 4)

This is the speed of a satellite in a circular orbit around the Earth. Note that v is proportional to 1/sqrt(r) and that the mass of the satellite has cancelled out.

2 years ago

Answered by Ryan, an A Level Physics tutor with MyTutor

## Still stuck? Get one-to-one help from a personally interviewed subject specialist

#### 116 SUBJECT SPECIALISTS

£36 /hr

Degree: Architecture and Environmental Engineering (Masters) - Nottingham University

Subjects offered:Physics, Maths+ 2 more

Physics
Maths
Design & Technology
-Personal Statements-

“Hi there, I have a passion for helping students achieve, and believe that with my 200+ hours of experience, we will be able to surpass the grades you want!”

£36 /hr

Degree: Theoretical Physics (Masters) - York University

Subjects offered:Physics, Science+ 3 more

Physics
Science
Maths
Further Mathematics
Chemistry

“Helping the striving and the struggling with caring, friendly and structured tuition. With 200+ hours of experience, offering Physics, Maths and Chemistry.”

£26 /hr

Degree: MBChB (Bachelors) - Birmingham University

Subjects offered:Physics, Maths+ 5 more

Physics
Maths
English
Chemistry
Biology
-Personal Statements-

“I am a passionate medical student who would love to teach the sciences and maths to any willing student! I would also love to help prospective medical students achieve their dreams!”

Currently unavailable: for new students

Degree: PhD in Astronomy (Doctorate) - Cambridge University

Subjects offered:Physics, Science+ 2 more

Physics
Science
Maths
Further Mathematics

“About Me:I'm a recent Physics graduate of Oxford University (1st Class Honours), currently working on a PhD in Astronomy at Cambridge University. My Astrophysics research is focused on characterising the atmospheres of planets orbit...”

### You may also like...

#### Posts by Ryan

What speed do satellites orbit at?

Where does the quadratic equation come from?

Why is Pluto not a planet any more?

#### Other A Level Physics questions

Explain the findings from Rutherford's alpha particle scattering experiment.

How can an object be accelerating when it's velocity is constant, and how does centripetal acceleration work.

How does stimulated emission work?

Explain, in terms of the behaviour of molecules, how a gas exerts a pressure on the walls of its container. (4)

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this.