Your interviewer will likely ask you knowledge-based questions to understand how well you are able to explain concepts to others. Be prepared for questions like this one by practicing a few possibilities ahead of time. In this case, a machine is any device that changes the direction or magnitude of a force applied, and a simple machine is the simplest possible design required to create that change. There are six classical examples of simple machines: lever, wheel and axle, pulley, inclined plane, wedge, and screw.