What is the net torque on a wheel with given dimensions and direction?

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Homework Help Overview

The discussion revolves around calculating the net torque on a wheel given specific dimensions and a defined positive direction for torque. The problem involves understanding the application of torque equations and the implications of angles in the context of rotational motion.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the calculations of torque based on given forces and distances, with one participant questioning the significance of a 30-degree angle in the problem. Others express confusion about its purpose and whether it affects the tangential nature of the forces involved.

Discussion Status

There is ongoing exploration of the problem, with participants attempting to clarify the role of the angle and its impact on the torque calculations. Some guidance has been offered regarding the tangential nature of the forces, but no consensus has been reached on the interpretation of the angle.

Contextual Notes

Participants are working with specific values for distances and forces, and there is mention of a potential discrepancy in the calculated net torque, indicating a need for further examination of the assumptions made in the calculations.

aaronb
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Homework Statement


find the net torque on the wheel about the axle through O, taking a = 7.00cm and b = 20.00cm. Assume the positive direction is counterclockwise


Homework Equations


torque = force x distance
torque = force x (radius x sin(phi))


The Attempt at a Solution


10.0 x .2m = -2 (because it's moving clockwise)
9.00 x .2m = -1.8
.07 x 12 x sin(30) = .42

net torque = -3.38 (this is off by 10%-100%)
 

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I don't understand what the 30 degree angle represents.
 
Me niether, do you think it was put there to confuse?
 
aaronb said:
Me niether, do you think it was put there to confuse?
Beats me. It looks like the 12 N force is tangential to the circle of radius a. Is that the case?
 
It is there to confuse. The net torque turned out to be -2.96 so the 12N force is tangential. Thanks for bringing that up to attention
 

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