Is My Assumption About Rope Tension Correct?

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Homework Help Overview

The discussion revolves around the tension in a rope system when one of the ropes is cut. The original poster questions whether their assumption that the remaining rope would support a vertical load of 5N is correct, and participants explore the implications of this scenario within the context of forces and tension in physics.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the implications of cutting one rope and the resulting tension in the remaining rope, questioning the original poster's assumptions about the vertical load. Some suggest considering the instantaneous tension after the cut, while others raise concerns about the correctness of the original assumption.

Discussion Status

The discussion is ongoing, with various interpretations being explored. Some participants have provided guidance on analyzing the forces involved, while others are still grappling with the assumptions and calculations presented. There is no explicit consensus on the correct approach or outcome yet.

Contextual Notes

Participants note that the weight of the object is not provided, which complicates the analysis. Additionally, there are references to the need for free body diagrams and the consideration of acceleration after the rope is cut, indicating that the problem may involve more complexity than initially assumed.

  • #31
haruspex said:
Yes, it's wrong. (That would be the right answer if the angle were 45 degrees.)
You have established that the weight is 10sin(60) N. Draw a free body diagram, exactly like the original diagram, but with only one rope.
So the rope is still at 60 degrees to the horizontal.
Let the tension in the rope be T. You know the weight, and hence the mass. The tension and the weight are the only forces acting, agreed?
Which way will the mass accelerate?
What can you therefore say about the forces orthogonal to that direction?

thank you very much for your guide..i will try your idea. i hope you have time to check it
 
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  • #32
stuc said:
thank you very much for your guide..i will try your idea. i hope you have time to check it
haruspex said:
Yes, it's wrong. (That would be the right answer if the angle were 45 degrees.)
You have established that the weight is 10sin(60) N. Draw a free body diagram, exactly like the original diagram, but with only one rope.
So the rope is still at 60 degrees to the horizontal.
Let the tension in the rope be T. You know the weight, and hence the mass. The tension and the weight are the only forces acting, agreed?
Which way will the mass accelerate?
What can you therefore say about the forces orthogonal to that direction?
4 ans.jpg


dear haruspex ... is it like this?
 
  • #33
stuc said:
View attachment 92448

dear haruspex ... is it like this?
The free body diagram is right, but you need to think about which way the acceleration must be. In your force analysis, you have summed the vertical components and assumed the total to be zero. In other words, you have supposed the acceleration to be horizontal. Clearly it will not be. Which way will it be?
 

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