Hi, I have forgotten quite a bit of my vibration studies, so I have a fairly basic question. Essentially, when you want to find the natural frequency of a single dof system, you use ω=√k/m. However, does anyone know a general procedure (not problem-specific) for finding "k" that is applicable to most SDOF problems. Examples would be something along the lines of a a rigid massless bar, hinged at one end, with a few springs attached and a mass at one end, or a rigid L-shaped bar hinged somewhere and gravity acting, or a water column in a U-shaped test tube (height vibrating with gravity)... I think you get the idea. Basically, I am looking for a series of steps that you would go through in all these situations in order to find the stiffness. Thanks.