ABSTRACT
The Generic First-Order System and its Step Response. Having shown a large number of mechanical first-order systems and having derived the system equations of two of these, it is now appropriate to define the generic first-order system and begin a study of its response to various types of inputs. As we have pointed out before, ideally one would use as input functions for analysis and design the actual input forces or motions encountered in the operation of the real system; however, these are generally somewhat unpredictable and peculiar to each specific application. Since we are at this point trying to obtain general information about system response, we use simple "standard" inputs such as steps and sine waves. As we progress to second-order and more complex systems, the step and sinusoidal response will serve as useful benchmarks for comparison. When designing a specific system, if lab or field testing has obtained time histories of typical inputs, our simulation methods allow us to use these to make our design more realistic. However, early stages of design will often use simple standard inputs.
