Calculating Moments: Forces on a Ratchet Wrench

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Discussion Overview

The discussion revolves around calculating the moments generated by two forces applied to a ratchet wrench, specifically focusing on the sum of the moments about the x-axis of a bolt. The context includes aspects of homework related to torque and moment calculations in a mechanical system.

Discussion Character

  • Homework-related, Technical explanation, Exploratory

Main Points Raised

  • One participant poses a question about how to calculate the moments at points A, B, and Q, and expresses uncertainty regarding the setup due to the angled pivots.
  • Another participant suggests that the first step involves determining the torque transmitted down the wrench extension and inquires if the concept of torques as vectors has been studied.
  • A participant indicates they believe moments are equivalent to torques and proposes a method to find the moment on the wrench extension by projecting it onto the x-axis using cosine.
  • Another participant agrees with the projection method suggested for calculating the moment.
  • One participant shares their attempt at the problem but expresses doubt about the correctness of their force vector.
  • A later reply mentions an inability to read an attachment and asks for clarification on the moment in the wrench extension.

Areas of Agreement / Disagreement

Participants express differing levels of confidence in their approaches, with some agreeing on the method of projection while others remain uncertain about their calculations. The discussion does not reach a consensus on the correct solution or methodology.

Contextual Notes

There are unresolved aspects regarding the definitions of moments and torques, as well as the specific calculations needed for the angled pivots. The discussion reflects varying interpretations of the problem setup.

MienTommy
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Homework Statement


Two 20 lb forces are applied to a ratchet wrench down at A and up at B to loosen bolt β. Find the sum of the moments of the two forces about the axis (x) of the bolt.

Homework Equations


What are the moments at point A, B, and Q?
How do I find the moment about the x-axis and not at the bolt β?

The Attempt at a Solution


Not sure how to set up the problem because of the different pivots Q and B which are angled.
hw1.png
 
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First step: What torque is transmitted down the 8" wrench extension?
Have you studied torques as vectors?
 
Yes I believe I have, but we call them moments? Could I just find the moment on the 8" wrench extension and project it on the x-axis by multiplying it by cos(45) to find the answer?
 
Yes, I believe that's right.
 
This is my attempt at the problem, I feel like it is wrong because of my Force vector.
 

Attachments

  • 20150907_205826.jpg
    20150907_205826.jpg
    14.4 KB · Views: 496
Unfortunately, I can open, but can't read your attachment. What is the moment in the wrench extension?
 

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