- #1

- 254

- 5

## Homework Statement

## Homework Equations

Singularity equations for beam deflection

$$\sum M_B=0=-M_0-R_AL-M_0$$

$$R_A=-\frac{2M_0}{L}$$

## The Attempt at a Solution

I know how to use singularity equations and all that but my problem is calculating the force especially when moment is involved. For example, from the above why is the sum of moment about B not equal to M

_{0}+R

_{A}L instead?

I really have no idea about this moment symbol. What are they rotating w.r.t.?

I guess I still don't really understand the conventions that are used in material science.

And for the moment applied on the beam as shown, is the force due to that moment acting downward or upward on that point?

In addition, how do I know that the moment(shown using the above circular arrow) is about what axix/reference? Cause the object will rotate in the opposite direction if the wrong reference is used. And to know what direction of its moment, I need to know the direction of the force at that point causing that moment, bringing me back to the question in the previous paragraph.

Thanks.

#### Attachments

Last edited: