Uniform circular motion question

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Homework Help Overview

The discussion revolves around uniform circular motion, specifically analyzing the forces acting on an object moving in a circular path at constant velocity. Participants are examining the correctness of force diagrams and equations for different positions of the object in motion.

Discussion Character

  • Mixed

Approaches and Questions Raised

  • The original poster attempts to verify their force equations for various positions of an object in uniform circular motion, questioning the relationships between tension, weight, and acceleration.
  • Some participants question the nature of acceleration in relation to the object's position and the reference frame used for analysis.
  • Others suggest considering the components of acceleration when the object is not at specific angles around the circle.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the forces involved in circular motion. There is a focus on clarifying the role of acceleration and how it relates to the coordinate system being used. No explicit consensus has been reached yet.

Contextual Notes

Participants are working within the constraints of uniform circular motion and are discussing the implications of using different coordinate systems for analyzing forces and accelerations.

Miike012
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Please look at the picture...
It is of a blue object in four locations that is swung around with a rope ( red line ) in a circle with constant velocity...

I wanted to know if my diagrams are correct for each separate location... and I was hoping someone could check my work below to tell me if it is correct...

1. ƩFx = 0; ƩFy = -T - W = (m)(a) and T = W

2. ƩFx = -T - W = (m)(a) ƩFy = 0 and T> W

3. ƩFx = 0; ƩFy = +T - W = (m)(a) and T>W

4. ƩFx = T - W = (m)(a) ƩFy = 0 and T>W
 

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And for an object somewhere other than the first four points... would the objects have both nonzero acceleration for ƩFx and ƩFy ?
 

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Is the angular velocity constant? If so, then there will be no acceleration "around" the loop. The idea is that the object has centripetal(sp?) acceleration towards the center. As the thing moves around the circle, the reference frame changes along with it. If acceleration is always pointing in the positive y (or whatever you called the center), then it can't have separate components can it?
 
I never said acceleration was around the circle... if you noticed I always said acceleration points to the sum of the vectors which is in the direction of Tension force...
I added another picture with a coordinate axis... I am not sure if it will make a diff,,,?

And velocity is constant, I mentioned uniform circular motion...
 

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Last edited:
I was referring to this:

Miike012 said:
And for an object somewhere other than the first four points... would the objects have both nonzero acceleration for ƩFx and ƩFy ?

Which the answer would have been no if you were using the coordinate system where the center point is positive y regardless of where the object is around the circle. (A polar type grid).

If you use the grid in your image then yes. Acceleration will have component vectors for the times when the object is not at 0, pi/2, pi, etc. which would have to be summed in your forces.
 

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