That’s the largest displacement from equilibrium omega is the angular frequency omega which we expressed in terms of radians per second the periods T 2 pi divided by omega is an expressed in terms of second and the frequency F which is one over T is what we call hertz number of cycles per second do not confuse omega with F there is a factor of 2 pi difference if I have a uniform circular motion and I project that uniform circular motion on to any line on the blackboard then l get a simple harmonic motion so I take for simplicity just this horizontal line but I could take any other line and let’s call this the X direction and let this point be X zero and I take an object which is rotating around here is the object it’s going around uniform circular motion