Rotational Motion of a slender rod

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Homework Help Overview

The discussion revolves around the rotational motion of a slender rod released from rest, focusing on the forces exerted by a pivot at one end of the rod. Participants are examining the relationship between normal force, tension, and centripetal force in this context.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are questioning the relationship between the normal force exerted by the pivot and the tension in the rod, as well as the nature of forces acting towards the pivot that contribute to centripetal force.

Discussion Status

The discussion is active, with participants exploring different interpretations of the forces involved. Some guidance has been offered regarding the role of normal force and its direction, but no consensus has been reached on the specifics of the forces acting on the rod.

Contextual Notes

There are indications of confusion regarding the forces at play, particularly in relation to the pivot's ability to exert both pulling and pushing forces on the rod. The problem setup may lack clarity on these dynamics.

zorro
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Homework Statement


A slender rod shown in the figure has a mass m and length l and is released from rest when theta=0 degrees. The horizontal and vertical components of force which the pin at A exerts on the rod at the instant shown in the figure is ?

attachment.php?attachmentid=32934&stc=1&d=1299788946.jpg

The Attempt at a Solution



I have some basic problems with this question.
The pivot at A exerts a normal force along the rod. Is the magnitude of this normal force equal to that of the tension in the rod?
 

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The force of the pin on the rod is equal to the tension in the rod at A, but the tension is not constant along the rod.

ehild
 
Ok, I drew this F.B.D. from what I understood:

attachment.php?attachmentid=32951&stc=1&d=1299837721.jpg


In the problems of a mass attached to a string and rotated in a vertical circle, we have tension acting on the mass towards the centre.
But I don't find any force towards the pivot/pin which is responsible for the centripetal force.
 

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Normal force will act in opposite direction. That along with component of Mg along the rod will give centripetal force.
 
Abdul Quadeer said:
But I don't find any force towards the pivot/pin which is responsible for the centripetal force.

The pivot can both pull and push the rod.

ehild
 
Thanks!
 

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