Understanding Vertical Circle Motion and Tension in Circular Motion

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Discussion Overview

The discussion focuses on the dynamics of circular motion in a vertical circle, specifically examining the factors affecting tension in the string and the role of gravitational components in determining motion. It includes theoretical aspects and conceptual clarifications related to forces acting on an object in circular motion.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants propose that the magnitude of tension is dependent on the weight of the object and its position relative to the horizontal diameter of the circle.
  • It is suggested that above the horizontal diameter, tension is lower due to a component of weight acting towards the center of the circle, while below it, tension increases as weight opposes the tension force.
  • One participant notes that the speed of the object also affects the tension, indicating that it should be included in the analysis.
  • There is a discussion about the component of weight represented by mg*sin(θ) and its role in creating tangential acceleration, with some participants noting that this force can either increase or decrease the object's speed depending on its direction relative to the velocity.

Areas of Agreement / Disagreement

Participants generally agree on the dependence of tension on weight, position, and speed, but there is ongoing exploration of how these factors interact, particularly regarding the effects of mg*sin(θ) on speed. The discussion remains somewhat unresolved as participants refine their understanding of these relationships.

Contextual Notes

Participants have not fully resolved the implications of speed on tension or the specific conditions under which mg*sin(θ) affects the object's motion. There are also assumptions about the nature of forces that have not been explicitly stated.

jsmith613
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This question is about circular motion in a vertical circle

Question 1:
would I be correct in assuming that the magnitude for tension is dependent on
(a) the weight of the object
(b) the position of the object with respect to the horizontal diameter of the circle

So above the 'horizontal diameter' tension is lower than below the 'horizontal diameter' because a component of weight acts towards the circle centre.
When it lies ON the circumference AT the 'horizontal diameter' ONLY tension provides the centripetal force
BELOW the 'horizontal diameter' tension increases because weight opposes the tension force

Is this all correct?

Question 2:
If you look at the free body diagram attached, mg*sin(θ) is present. What does this compoenent of weight do??

Thanks
 

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jsmith613 said:
Question 1:
would I be correct in assuming that the magnitude for tension is dependent on
(a) the weight of the object
(b) the position of the object with respect to the horizontal diameter of the circle
Yes, but also the speed of the object.

So above the 'horizontal diameter' tension is lower than below the 'horizontal diameter' because a component of weight acts towards the circle centre.
When it lies ON the circumference AT the 'horizontal diameter' ONLY tension provides the centripetal force
BELOW the 'horizontal diameter' tension increases because weight opposes the tension force

Is this all correct?
Sounds good, as long as you include the effect of speed.

Question 2:
If you look at the free body diagram attached, mg*sin(θ) is present. What does this compoenent of weight do??
It creates a tangential acceleration.
 
Doc Al said:
It creates a tangential acceleration.

in some cases mgsinθ will be in the same direction as velocity and in others it will be in the exact opposite...I presume this is the force that will cause the speed of the object to vary?
 
jsmith613 said:
in some cases mgsinθ will be in the same direction as velocity and in others it will be in the exact opposite...I presume this is the force that will cause the speed of the object to vary?
That is correct.
 
Doc Al said:
That is correct.

thanks
 

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