Finding the Tension in terms of weight and the angle of incline

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Homework Help Overview

The problem involves two blocks, each with weight ω, positioned on a frictionless incline at an angle θ. The objective is to calculate the tension in the rope connecting the two blocks in terms of ω and θ.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss breaking down the weight into components and applying Newton's second law. There are questions regarding the feasibility of a frictionless incline holding the blocks in place, with some suggesting that tension is the key factor. Others express confusion about the setup and the implications of the blocks being stationary.

Discussion Status

The discussion is ongoing, with various interpretations of the problem being explored. Some participants have provided insights into the relationship between tension and the forces acting on the blocks, while others are questioning the initial assumptions made in the problem statement.

Contextual Notes

There is a noted ambiguity regarding the mechanics of a frictionless incline and how it can support the blocks without motion. Additionally, the role of acceleration in the context of the problem is under scrutiny.

Yosty22
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Homework Statement



Two blocks, each with weight ω, are held in place by a frictionless incline.
In terms of ω and the angle θ of the incline, calculate the tension of the rope connecting the two blocks.

Homework Equations



ƩF=ma

The Attempt at a Solution



Since it is on a tilted incline, with angle θ, I made the x and y-axis tilted for the free body diagram. This means that ω, the weight, can be broken down into components ωx, which is parallel to the tension, and ωy, perpendicular to tension. In this case, I assumed that all forces acting in the x-direction (parallel to the tension) were ωx and T. I then used the equation ƩF=max and plugged in values and solved for T. First, I put "ωsinθ" in place of ωx, making the equation ωsinθ+T=ma. Solving for T, I get T=ma-ωsinθ. Is this correct? It looks a little odd to me.
 
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I think something is missing in the statement of the problem. How can a frictionless incline hold anything in place?
 
tms said:
I think something is missing in the statement of the problem. How can a frictionless incline hold anything in place?
No, they are held in place by tension.
 
Yosty22 said:

Homework Statement


Since it is on a tilted incline, with angle θ, I made the x and y-axis tilted for the free body diagram. This means that ω, the weight, can be broken down into components ωx, which is parallel to the tension, and ωy, perpendicular to tension. In this case, I assumed that all forces acting in the x-direction (parallel to the tension) were ωx and T. I then used the equation ƩF=max and plugged in values and solved for T. First, I put "ωsinθ" in place of ωx, making the equation ωsinθ+T=ma. Solving for T, I get T=ma-ωsinθ. Is this correct? It looks a little odd to me.
Since the blocks are held in place there is no acceleration so ma=0⇔ƩFx=0. And remember, there are two blocks.
 
Last edited:
lep11 said:
No, they are held in place by tension.
I can't picture the setup.
 
Sorry guys, this is the setup. I have looked at it a few more times and still get the same thing. Am I doing something wrong?
 

Attachments

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Since the blocks are not moving, what is the acceleration?
 
Your answer above is wrong.

It may help to tell you that the tension in that rope would only depend on the mass of B (and not A). Remember the tension in string is equal to the force with which gravity is pulling the mass down the slope.
 
Last edited:

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