How Long Does Moon E Take to Orbit Planet?

  • Thread starter Thread starter Want to learn
  • Start date Start date
  • Tags Tags
    Moon Orbit Planet
Click For Summary

Homework Help Overview

The problem involves two moons orbiting a planet in circular orbits, with a focus on determining the orbital period of moon E based on the known period of moon D and their respective orbital radii.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the relationship between the orbital periods of the moons and their distances from the planet, referencing Kepler's laws. There is uncertainty about whether the period of moon E can be directly inferred from that of moon D.

Discussion Status

Some participants have suggested reconsidering the application of Kepler's laws, particularly the third law, while others express confusion about the implications of orbital radius on the period. There is no consensus yet on the correct approach to the problem.

Contextual Notes

Participants note the absence of specific equations in the original post and question the assumptions made regarding the relationship between the orbital periods and radii of the moons.

Want to learn
Messages
23
Reaction score
0

Homework Statement



Two moons orbit a planet in nearly circular orbits. Moon D has orbital radius r, and moon E has orbital radius 4r. Moon D takes 20 days to complete one orbit. How long does it take for moon E to complete one orbit


Homework Equations



None - I think


The Attempt at a Solution



I am hoping that this problem is not complicated. Since it takes 20 days for moon D with radius r, it would take 80 days for moon E with radius 4r?

Is my reasoning correct ??
 
Physics news on Phys.org
No, it isn't. What do Kepler's laws have to say about this problem?
 
Is it just 20 days the same as moon D?

A line drawn from the sun to any planet sweeps out equal areas in equal time intervals.

Does the size - radius matter then?
 
Ok the above doesn't make sense.

Then I don't know, really.
 
It's not just 20 days.

Keplers second law is only valid for the same planet or moon (and it's trivial for a circular orbit)
Try the third law.
 

Similar threads

Calculating Angle & Speed to Reach Planet's Moon from Station Orbit
  • · Replies 1 ·
Replies
1
Views
2K
Finding distance between Earth and Moon in gravitational fields
  • · Replies 5 ·
Replies
5
Views
2K
A satellite in orbit in a system with one planet and two moons
  • · Replies 1 ·
Replies
1
Views
2K
Does the moon orbit as a classical particle?
  • · Replies 1 ·
Replies
1
Views
2K
From circular orbit to elliptical orbit
  • · Replies 3 ·
Replies
3
Views
3K
ORBIT: change in orbital distance
  • · Replies 10 ·
Replies
10
Views
2K
Time of satellite orbit around moon?
  • · Replies 7 ·
Replies
7
Views
2K
What is the gravitational acceleration on the surface of Moon B?
  • · Replies 1 ·
Replies
1
Views
2K
How Do You Calculate the Moon's Speed and Acceleration in Its Orbit?
  • · Replies 6 ·
Replies
6
Views
3K
Consider a moon that is 1.15 x 10^6 km from the planet it is orbiting .
  • · Replies 3 ·
Replies
3
Views
2K