by Gail Belsky. The term sleep disorder may suggest someone tossing and turning all night, but lying awake for hours with insomnia is just one example of many conditions that affect how you sleep and function during the day. In fact, you can have a sleep disorder and not even know it. Next: How long to snooze.
A U wave as seen on ECG. An electrocardiogram of an 18-year-old man showing U waves, most evident in lead V3. The U wave is a wave on an electrocardiogram that is not always seen. It is typically small, and, by definition, follows the T wave. U waves are thought to represent repolarization of the papillary muscles or Purkinje fibers.
Hmm, but the second of the two sine functions, though it involves t, but it also involves v as Ï=kv. Means there is a term of wave velocity in the equation of a standing wave. Doesn't that signify the standing wave moves? It does not, obviously, but then what does the v here stand for? What does the v here represent in the equation of a standing wave? If a quantity is related to some velocity it does not mean that the quantity moves. Speed is defined only for travelling waves: Think of the water waves, you see the peaks - wave-fronts moving along. The standing wave does not travel. The nodes are always at the same positions. Ï and k are two parameters, and y, the displacement from equilibrium, depends on both. v is a constant, the speed of any wave of certain kind in the given medium determined by some physical properties of the matter. The wave is a motion, periodic both in space and time.