Pulling a block along a surface using a string inclined at an angle

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Homework Help Overview

The discussion revolves around the forces acting on a block being pulled along a surface by a string inclined at an angle. Participants are exploring the concepts of tension, force components, and equilibrium conditions in this context.

Discussion Character

  • Conceptual clarification, Assumption checking, Mixed

Approaches and Questions Raised

  • Participants are questioning the relationship between tension and force components, particularly regarding the validity of equating force to length. There are suggestions to derive equations based on the net force components being zero when acceleration is absent.

Discussion Status

The discussion is active, with participants providing feedback on each other's reasoning and encouraging the use of LaTeX for clarity in equations. There is an acknowledgment of the importance of maintaining the original post for clarity, indicating a collaborative effort to refine understanding.

Contextual Notes

Some participants express confusion over the definitions and relationships of forces involved, particularly tension, and there is a mention of external resources, such as a YouTube video, that may have influenced their understanding.

Memo
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Homework Statement
A block with a weight of P is being pulled by a string of length l at a constant rate and an angle. The distance between the tip of the block to the surface is h. (see the photo below)
Find the kinetic coefficient of friction (the string is attached to the centre of the block)
Answer hint: k=(F*sqrt(l^2-h^2))/(Pl-Fh)
Relevant Equations
f=k*N
00001 (1).jpg

00001.jpg
 
Last edited:
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Memo said:
The tension force along the string is equal in magnitude and opposite in direction to the force being applied
I don't understand this. The tension is ##\vec F## and has the same magnitude and direction.
Memo said:
Can I put Fx=sqrt(l^2-h^2) and Fy=h?
No you cannot. It says that a force is equal to a length which is never true.

Try getting two equations, saying that vertical and horizontal components of the net force are zero which is always true when the acceleration is zero.
 
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kuruman said:
I don't understand this. The tension is ##\vec F## and has the same magnitude and direction.

No you cannot. It says that a force is equal to a length which is never true.

Try getting two equations, saying that vertical and horizontal components of the net force are zero which is always true when the acceleration is zero.
I watched a somewhat relevant YouTube video and saw there was also the tension force, so I included it. But I've my problems, thank you so much!
 
Your solution looks correct. For future reference, please don't edit the original post because it can be confusing to people who have seen it and are trying to respond to it. Corrections or additions to the first post should be posted separately.

Also, you are encouraged to use LaTeX to write equations. It's a useful skill and makes everybody's life much easier. Click on the link "LaTeX Guide" (lower left above "Attach files") to learn how.
 
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