Can I add centrifugal acceleration?

Click For Summary

Discussion Overview

The discussion revolves around deriving the centrifugal and Coriolis accelerations of the Moon when it is at its furthest point from the Sun and orthogonal to the radius between the Earth and the Sun. Participants explore the implications of these accelerations in the context of gravitational forces and orbital mechanics.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant states that the Coriolis acceleration will be zero when the Moon is furthest from the Sun due to the velocity of the Moon being parallel to the angular frequency of the Earth-Moon system's trajectory around the Sun.
  • Another participant questions the interpretation of angular frequency and suggests that using masses and distances might provide a more straightforward approach to calculating accelerations.
  • It is noted that gravitational forces can be used to calculate acceleration, but one participant emphasizes that the magnitudes of centrifugal accelerations cannot simply be added unless they are in the same direction.
  • There is a challenge regarding the presence of Coriolis effects in this scenario, with a suggestion that centripetal acceleration might be the more relevant term.
  • One participant proposes two approaches to derive the net acceleration of the Moon, considering the contributions from both the Earth and the Sun, while correcting a previous claim about adding centrifugal accelerations.

Areas of Agreement / Disagreement

Participants express differing views on the treatment of Coriolis and centrifugal accelerations, with some questioning the relevance of Coriolis effects and others debating the correct method for combining accelerations. No consensus is reached on the correct approach to the problem.

Contextual Notes

Participants highlight the complexity of vector addition in the context of gravitational forces and the need for careful consideration of coordinate systems when calculating accelerations.

FXpilot
Messages
2
Reaction score
0
So the problem is asking me to derive the centrifugal and coriolis accelerations of the moon when it is furthest from the Sun and when it is orthogonal to the radius between Earth and the Sun.

Given:
Radius of Moon's Orbit around Earth
Radius of Earth's Orbit around Sun
Mass of Earth
Mass of Sun
gif.gif
= Angular Frequency of the revolution of the Earth around the Sun
gif.gif
= Angular Frequency of the Revolution of the Moon around the Earth

I am trying to figure out the first part.
I know that the coriolis acceleration is going to be zero when the moon is furthest from the Sun because the velocity of the moon is parallel to the angular frequency of the trajectory of the Earth Moon system around the sun.

I already derived that the centrifugal acceleration that the moon experiences by the Earth is
gif.gif


T being the period of the moon around the Earth So would the total centrifugal acceleration that the Moon experiences be the :

Centrifugal Acceleration of the moon by Earth + Centrifugal Acceleration of the moon by Sun?

So

gif.gif


P being the period of the Earth moon system around the sun

Thanks
 
Physics news on Phys.org
FXpilot said:
I know that the coriolis acceleration is going to be zero when the moon is furthest from the Sun because the velocity of the moon is parallel to the angular frequency of the trajectory of the Earth Moon system around the sun.
A frequency does not have a direction. The angular velocity does have one, but it is never parallel to the motion of moon.
FXpilot said:
So would the total centrifugal acceleration that the Moon experiences be the :

Centrifugal Acceleration of the moon by Earth + Centrifugal Acceleration of the moon by Sun?
Could work, but you can also use the masses and distances, which is less dependent on handling different coordinate systems correctly.
 
mfb said:
A frequency does not have a direction. The angular velocity does have one, but it is never parallel to the motion of moon.
Could work, but you can also use the masses and distances, which is less dependent on handling different coordinate systems correctly.

What do you mean by masses and distances?
 
The acceleration comes from gravity, and you have everything you need to calculate the gravitational forces.
 
You have calculated the magnitude of the accelerations, but you can not simply add the magnitudes unless the accelerations are in the same direction. At any moment, the centrifugal accelerations are vectors created by the gravitational force of the Earth and the Sun. They point toward the Earth and Sun, respectively. Vectors of the magnitude that you calculated can be added and the resulting vector is the total acceleration.
 
FXpilot said:
So the problem is asking me to derive the centrifugal and coriolis accelerations of the moon when it is furthest from the Sun and when it is orthogonal to the radius between Earth and the Sun.
Why would there be any coriolis effect here? Also, do you mean centripetal acceleration? The acceleration vectors are toward the sun and the Earth centres.

AM
 
(+ denotes vector addition operator)
FXpilot said:
derive the centrifugal and coriolis accelerations of the moon when it is furthest from the Sun
different particles of moon have different accln . if consider com of moon--
since in this case net accln is parallel to radius
1st approach) centrifugal acceleration * (-1) = proj of net acceleration normal to net velocity= net acceleration = (g due to earth) + (g due to sun)
(g=Gm/rr)
2nd approach) since in this case centripetal accln equals net accln and assuming force bet sun and moon negligible to other forces(since it is about 100 times less than force bet Earth and sun)
net accln of moon= (accln of moon in earth(com) frame) +(accln of earth(com) in sun frame)
=
FXpilot said:
proxy.php?image=https%3A%2F%2Flatex.codecogs.com%2Fgif.png


P being the period of the Earth moon system around the sun
this is correct
but this---
FXpilot said:
total centrifugal acceleration that the Moon experiences be the :

Centrifugal Acceleration of the moon by Earth + Centrifugal Acceleration of the moon by Sun
is incorrect
total centrifugal acceleration that the Moon experiences be the
Centrifugal Acceleration of the moon by Earth + Centrifugal Acceleration of the earth by Sun
and (4*pi*pi*r /(P*P)) =Centrifugal Acceleration of the earth by Sun
 

Similar threads

  • · Replies 19 ·
Replies
19
Views
2K
Replies
9
Views
4K
  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 32 ·
2
Replies
32
Views
4K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 15 ·
Replies
15
Views
3K
  • · Replies 13 ·
Replies
13
Views
10K
  • · Replies 41 ·
2
Replies
41
Views
4K
  • · Replies 4 ·
Replies
4
Views
3K
Replies
17
Views
10K