Is Your Calculation of Net Torque Correct?

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Homework Help Overview

The discussion revolves around calculating net torque in a physics problem, focusing on the application of torque equations and the distances from the pivot point for various forces.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • The original poster attempts to calculate net torque using given forces and distances but questions the correctness of their approach. Some participants question the distances used in the calculations, suggesting corrections to the lever arms. Others clarify the concept of torque and how to determine the effective distance from the pivot.

Discussion Status

The discussion is active, with participants providing clarifications and corrections regarding the distances involved in the torque calculations. There is a productive exchange of ideas, but no explicit consensus has been reached on the original poster's calculation.

Contextual Notes

Participants are navigating through the definitions and calculations of torque, with some confusion about the geometry involved in determining distances from the pivot point. The original poster has expressed uncertainty about the setup and the impact of certain forces on the net torque calculation.

Intrusionv2
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Homework Statement



Find net torque.
2dbqwl0.jpg


Homework Equations

T = F(d) and T = F(d)sinx

Torque = T
Force = F
d = distance

The Attempt at a Solution



100(0) - 200(4)sin40 - 120(14) + 150(8) = -994.2 Nm

Did I do this correctly? Notice I crossed out the 400N also because I think that it does not affect it.
 
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Welcome to PF.

I think your second term is 6m from the pivot not 4m.

Your bottom force - 150N - is 15m from the pivot not 8m as your equation suggests.
 
Ah, thanks, but how is 150N 15m away from the pivot point? Do I just go up? Sorry I do not understand :(
 
Intrusionv2 said:
Ah, thanks, but how is 150N 15m away from the pivot point? Do I just go up? Sorry I do not understand :(

It's the projection of the force to a line that is perpendicular to the pivot. That is the way you should be taking Torque.

For instance the one at an angle of 40° if you extended that out you would see that the lever arm that is perpendicular to the force is Sin40° times the 6m length.

For the bottom force it is acting horizontally, but it is acting through the vertical line from the pivot at a distance of 14 + 1 = 15.
 
Ahhh...that clears up so many things. Thank you so much!
 

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