# Mini-Quiz: Orbital Motion Relative to Another Object

by Ron Kurtus (revised 14 May 2011)

Take this Mini-Quiz to check your understanding of the lesson material.

1. Why would you want to show the orbit of one object with respect to the other?

The is a convenient point of view

Just as an exercise in mathematics

You only consider orbits with respect to the CM

2. How do you determine the orbital velocity of one object relative to the other?

You add their tangential velocity equations relative to the CM

You make M >> m

You add their tangential velocities relative to each other

3. How can the Earth appear to orbit the Moon?

It is impossible, because the Earth is too big to orbit the Moon

It depends on whether it is a full or new Moon

It happens if you view the Earth from the surface of the Moon

If you got all three correct, you are on your way to becoming a Champion in Physics. If you had problems, you had better look over the material again.

Set an example for others to follow

## Resources and references

Ron Kurtus' Credentials

### Websites

Center of Mass Calculator - Univ. of Tennessee - Knoxville (Java applet)

Center of Mass - Wikipedia

Gravitation Resources

### Books

Do you have any questions, comments, or opinions on this subject? If so, send an email with your feedback. I will try to get back to you as soon as possible.

## Students and researchers

www.school-for-champions.com/science/
mini-quiz_gravitation_orbital_motion_relative.htm

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