Analyzing Net Forces and Equations in a Driven Mass on a Circular Path System

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Homework Help Overview

The discussion revolves around analyzing a system involving net forces and equations for two masses moving along a circular path, influenced by springs and an external force. The equations presented appear to relate to dynamics, specifically Newton's second law, but there are concerns about clarity and completeness in the formulation.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants are examining the equations of motion for two masses, questioning the clarity of terms and the inclusion of angular variables. There are discussions about potential sign errors and the implications of different rotational directions for the masses.

Discussion Status

There is active engagement with the equations, with participants suggesting clarifications and questioning the assumptions made in the setup. Some participants are exploring the implications of different configurations and forces acting on the masses, indicating a productive exploration of the problem.

Contextual Notes

Participants note that the equations may be incomplete or unclear, particularly regarding the roles of certain variables and the need for additional definitions. There is an emphasis on the need for LaTeX formatting to improve clarity in the presentation of equations.

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Homework Statement
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Relevant Equations
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1594764359971.png

1594764406949.png

What you think about this system:?

F*cosw - k(x1+x2) - k(x1-x2) = mx1''
-k(x1+x2) - k(x1-x2) = mx2''
 

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LCSphysicist said:
What you think about this system:?

F*cosw - k(x1+x2) - k(x1-x2) = mx1''
-k(x1+x2) - k(x1-x2) = mx2''
It would help if you could post this using LaTeX (see the LaTeX Guide link at the lower left of the Edit window. Thanks.

Also, could you please explain the equations you are trying to write? It looks like you are trying to write F=ma type equations, but your terms are not clear to me (especially since some parts seem to be missing). Also, at some point fairly soon you will need to include the variables ##\theta_1## and ##\theta_2## to denote the positions of the two masses as functions of time...
 
LCSphysicist said:
What you think about this system:?

F*cosw - k(x1+x2) - k(x1-x2) = mx1''
-k(x1+x2) - k(x1-x2) = mx2''
Some sign errors.
berkeman said:
you will need to include the variables θ1 and θ2
The x1 and x2 can be taken as angles, or arc lengths, whatever.
 
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Maybe the problem is adopt one clockwise and another counterclockwise?
This came to my mind when i attack the problem, but i went on just to see if i could try by this another way as well as adopt just clockwise [or counterclokwise]. But what i can't refut is why would it be wrong, that is:

## F*cos(wt) - [k(x1+x2)] - k(x1-x2) = m \frac{d^2 x1}{dt^2} ##
## [-k(x1+x2)] - k(x1-x2) = m \frac{d^2 x2}{dt^2} ##

the bracket being to the left spring:
If x2 = 0 and x1 > 0, will be a force on m1 in its negative direction, as to x2. Works as well to x1<0

Without bracket to the right spring:

If x2 = 0 and x1 > 0, will be a force on m1 in its negative direction, as to x2. Also works to x1<0

About the Latex, i will try ;)
 
LCSphysicist said:
Maybe the problem is adopt one clockwise and another counterclockwise?
This came to my mind when i attack the problem, but i went on just to see if i could try by this another way as well as adopt just clockwise [or counterclokwise]. But what i can't refut is why would it be wrong, that is:

## F*cos(wt) - [k(x1+x2)] - k(x1-x2) = m \frac{d^2 x1}{dt^2} ##
## [-k(x1+x2)] - k(x1-x2) = m \frac{d^2 x2}{dt^2} ##

the bracket being to the left spring:
If x2 = 0 and x1 > 0, will be a force on m1 in its negative direction, as to x2. Works as well to x1<0

Without bracket to the right spring:

If x2 = 0 and x1 > 0, will be a force on m1 in its negative direction, as to x2. Also works to x1<0

About the Latex, i will try ;)
Consider the case x1=-x2, so both move the same direction around the hoop. What net forces will spring exert on them? What do your equations give?
 
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