# Mini-Quiz: Circular Planetary Orbits

by Ron Kurtus

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

1. How would the orbital velocity of the Moon be affected if it were further from the Earth?

The velocity would increase

The velocity would be slower

The velocity would stay the same

2. Why is the simple equation for orbital velocity used in the Earth-Sun case?

The Earth is too far from the Sun to use anything else

The simple velocity equation is used to get a more accurate result

The Sun is so much larger than the Earth that the CM is almost at its center

3. Why is the CM between Jupiter and the Sun outside the Sun's surface?

Jupiter has such strong gravity that it pulls the CM toward it

The mass of Jupiter is large enough that the CM is outside the Sun

It is only an illusion that the CM is outside the Sun's surface

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.

Be amazed with science

## Resources and references

Ron Kurtus' Credentials

### Websites

Orbital Mechanics - Rocket & Space Technology by Robert A. Braeunig

How Satellites Work - HowStuffWorks.com

Orbit - Wikipedia

Circular orbit - Wikipedia

Acceleration due to Gravity Calculations - from Western Washington University

Gravitation Resources

### Books

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## Students and researchers

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

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