Recent content by Elfrid Payton

Ah, I can use reaction forces for the other member! Damn, that should have been really obvious. So there's no real way to determine direction without using math?

1. The Problem 2. The Free Body Diagram 3. The Question I've always had trouble determining the direction of the vertical and horizontal components in FBDs for statics problems, especially for a pin. Prior to looking at the solution, I wasn't sure on almost all of the directions of the...

The calculations are not the problem. Figuring out whether the members are undergoing tension or compression for the FBDs is what I'm having trouble with.

When examining a member, how do I tell whether it is undergoing tension or compression? It's more of a general question, but since a visual might help with the explanation, this could be useful:

Ah, so only restorative forces are included in differential equations for oscillations, and gravity is never a restorative force?

Problem: http://i.imgur.com/o8Q1RGZ.png Solution: http://i.imgur.com/IYiXITJ.png To get d2y/dt2+ρgLby/M=0, you have to sum the forces and set them equal to Ma. But what happens to Mg when you sum the forces?