Newton's force and circular acceleration

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Homework Help Overview

The problem involves analyzing the forces acting on a watch being swung in a vertical circle, specifically calculating the tension in the chain at a given angle. The context is rooted in Newtonian mechanics, focusing on circular motion and force dynamics.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to derive the tension in the chain using free body diagrams and force balance but questions the accuracy of their result. Some participants suggest checking significant figures, while others express uncertainty about the relevance of significant figures in the context of the problem.

Discussion Status

The discussion is ongoing, with participants providing feedback on the original poster's calculations and considerations regarding significant figures. There is no explicit consensus on the correctness of the original answer, but some participants have expressed confidence in the calculations.

Contextual Notes

Participants note the potential impact of significant figures on the correctness of answers submitted to the website, indicating a possible area of confusion or misinterpretation related to grading criteria.

homo-sapiens
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Homework Statement



Your niece finds her father's watch. The light watch chain has a length of 35 cm, and the mass of the watch is 190 g. Your niece swings the watch in a vertical circle, maintaining the speed of the watch at 2.4 m/s. Find the tension in the chain when it makes an angle of 43° with respect to the vertical. (Assume the watch is closer to the top of the circle than the bottom. Also assume the radius of the circle is 35 cm.)

Homework Equations



F=ma
a=v^2/r

The Attempt at a Solution



I drew free body diagrams, balanced the forces and derived at an equation. The answer I got was 1.765 Newton which was incorrect. Can someone please tell me what mistake I made??

http://puu.sh/bMw81/df16b4f7f9.png [/B]
 
Last edited by a moderator:
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your work looks good but watch significant figures. Try 1.8 N.
 
i am pretty sure, sig fig doesn't matter to the website, because i have submitted answers which definitely has wrong sig figs but is still marked correct. thanks for the advice though, need to be careful of sig figs on tests and exams.
 
homo-sapiens said:
i am pretty sure, sig fig doesn't matter to the website, because i have submitted answers which definitely has wrong sig figs but is still marked correct. thanks for the advice though, need to be careful of sig figs on tests and exams.
I think your answer is correct.I have checked the calculation too.
 
http://puu.sh/bMPIE/b03325effc.png
I guess I should check with my prof about it.
thanks for the reaffirmation
 
Last edited by a moderator:
homo-sapiens said:
http://puu.sh/bMPIE/b03325effc.png
I guess I should check with my prof about it.
thanks for the reaffirmation
You are welcome.
 
Last edited by a moderator:

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