Find Centre of Mass: Angle AC & Horizontal- 9.46°

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Homework Help Overview

The problem involves determining the angle between a line AC and the horizontal for a lamina that is free to rotate about a fixed horizontal axis. The lamina is in equilibrium, and the original poster references a solution that includes a specific angle of 9.46 degrees.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster questions the validity of their understanding and the solution provided, particularly regarding the angle theta shown in the working out. Other participants explore the implications of the lamina's position and its behavior when released.

Discussion Status

The discussion is ongoing, with participants reflecting on their interpretations and questioning the reasoning behind the inclusion of theta in the solution. Some participants seem to find clarity in the reasoning presented, while others continue to seek understanding.

Contextual Notes

There is mention of a screenshot attached to the thread, which may contain additional information relevant to the problem. The participants are navigating assumptions about the lamina's behavior and the definitions of angles involved.

Kajan thana
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Homework Statement


The lamina is free to rotate about a fixed smooth horizontal axis, perpendicular to the plane of the lamina, passing through the point A. and hangs in equilibrium.
Find the angle between AC and the horizontal.

I have attached a the solution to the question, it seems like there is no line to the question and theta there are showing in the working out.

Homework Equations


I think the answer is 9.46 degree as tanφ= 1/6

The Attempt at a Solution

.[/B]
I have attached screenshot to this thread. Is the solution wrong or have I been thinking in a wrong way? What are looking at that theta shown in the screenshot?
 

Attachments

  • Screen Shot 2017-01-29 at 22.21.04.png
    Screen Shot 2017-01-29 at 22.21.04.png
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Last edited by a moderator:
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Kajan thana said:
have I been thinking in a wrong way

More like thinking upside down . If you were holding the lamina in the position shown what would happen when you let go of it ?
 
lamina will turn so the centre of mass is below the pivot.
 
That's it .
 
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Nidum said:
That's it .
yes but my question why have they goy theata there when they ask for the theta between the horizontal and AC
 
Last edited:
Nidum said:
That's it .
i thought about it. It makes sense what they have done.
 

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