Rotating Bodies Around Origin: Analyzing Motion & Dynamics

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Homework Help Overview

The problem involves two bodies of equal mass that are initially at rest and positioned at specific coordinates, with a focus on their motion and dynamics as they rotate around the origin while maintaining a fixed distance between them.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to derive equations for the horizontal and vertical distances between the bodies, leading to a discussion about the nature of the accelerations involved. Some participants question the introduction of time in the equations and the validity of the assumptions made regarding the relationships and definitions used.

Discussion Status

Participants are actively questioning the assumptions and definitions presented by the original poster, particularly regarding the introduction of time and the nature of the accelerations being complex. There is an indication that further clarification and additional context from the problem statement may be necessary for a productive discussion.

Contextual Notes

There is mention of a relationship that is not fully detailed, and some participants express confusion over the definitions and conditions provided in the problem statement. The distance between the two bodies is noted to be 2a, which may impact the interpretation of the problem.

Silviu
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Homework Statement


Hello! I have 2 bodies initially at rest, of equal masses with the distance between them a and coordinates ##(a cos(\theta),a sin(\theta))## and ##(-a cos(\theta),-a sin(\theta))##. If we denote ##a_x## and ##a_y## the horizontal and vertical distance between them they satisfy a relationship which gets reduced to what I write in 3. Show that they rotate around the origin (keeping the distance between them fixed)

Homework Equations

The Attempt at a Solution


##\frac{d^2 a_x}{dt^2} = A(1+i)\omega^2e^{-i\omega t}## and ##\frac{d^2 a_y}{dt^2} = A(-1+i)\omega^2e^{-i\omega t}##. So I get ##a_x = A(1+i)e^{-i \omega t}+Bt+D## and ##a_y = A(-1+i)e^{-i \omega t}+Et+F##. If I put the condition to be stationary in the beginning (t=0), I get ##B=A(1+i)## and ##E=A(-1+i)## But I am kinda stuck. What should I do from here?
 
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Hi,
Where on Earth does your first = in the attempt come from ? There is no mention of ##t## at all in your problem statement !?
Silviu said:
they satisfy a relationship which gets reduced to what I write in 3
Which one (what relationship) ? Says who ?
 
BvU said:
Hi,
Where on Earth does your first = in the attempt come from ? There is no mention of ##t## at all in your problem statement !?
Which one (what relationship) ? Says who ?
The whole statement is long so I just put the last version of it. It is given and equality that involves some things defined in the book so I just put the point where I got stuck. t is the time
 
Silviu said:
The whole statement is long so I just put the last version of it. It is given and equality that involves some things defined in the book so I just put the point where I got stuck. t is the time
Ok, but it would help if you were to make a three way distinction: the part of the question you are trying to solve, what you have already established from earlier parts, and your attempt at this part.
I assume that your two expressions for the accelerations fall into the middle section, but I cannot understand how they can be right. The resulting accelerations will be complex. Shouldn't they be real? If it is reasonable that they are complex you will nee to post much more of the given question.
Silviu said:
distance between them a
The distance between the coordinates you quote is 2a.
 

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