Calculating Moments: Forces on a Ratchet Wrench

AI Thread Summary
To calculate the sum of the moments of two 20 lb forces on a ratchet wrench about the x-axis of bolt β, one must consider the torque transmitted through the 8" wrench extension. The discussion highlights confusion regarding the different pivot points, Q and B, and how to appropriately project the torque onto the x-axis. It suggests using the cosine of the angle (cos(45)) to find the moment in the wrench extension. Participants emphasize the need to clarify the relationship between torque and moments, indicating that they may be used interchangeably in this context. The overall focus is on accurately determining the moments and understanding the mechanics involved in the 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: 465
Unfortunately, I can open, but can't read your attachment. What is the moment in the wrench extension?
 

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