# Statics: Moment about an axis

## 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.

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
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Unfortunately, I can open, but can't read your attachment. What is the moment in the wrench extension?