This text is meant to accompany class discussions. It is not everything there is to know about uniform circular motion. It is meant as a  prep for class. More detailed notes and examples are given in the class notes, presentations, and demonstrations. See the links below.
 

Superposition for waves

 

This video will describe what wave superposition is and provide some simple examples that you can try.

This video can be found on YouTube at https://youtu.be/2HNQ9Ux05IE

 

When waves have a phase shift of 1/2 a wavlength from each other, they cancel each other out. The result is the color of light that this wavelength corrosponds to will disapear. The sound frequency would also vanish. (How cool is that. Hint: Have you ever heard of noise cancelling headphones?) This unit will describe the circumstances this occurs under and what some of those mysterious circumstances mean for Quantum mechanics. (It crazy weird.)

 

Wave Sources

 

Coherent waves are waves that, when produced are identical. Same phase and frequency -therefore the same wavelength and speed. This can be done with sound by connecting two or more speakers to the same output. For example, connecting all of the speakers in a car only to the stereo's right channel such that every speakers' positives are connected to the right channel's positive and all of the speakers' negatives are connected to the right channel's negative.

The easiest modern way to make make light coherent is to use a laser. Even an inexpensive laser pointer will work. The second way is to pass a beam through a single slit. To make two coherent sources have that same beam pass through a double slit or diffraction grating.

It is assumed that all the waves sources discussed in this chapter are coherent.

 

Example
  • Question
  • Solution

Two speakers are placed in an anechoric chamber. (This is a room where does not reflect.) They are each fed the same sound signal of 310 Hz. If one speaker is placed directly behind the other and no sound is heard when standing directly in front of the speakers, then how far apart of the speakers?

 
The Famous Double Slit Experiment

 

In 1801 Thomas Young performed an experiment called the double slit experiment. The experimnet proved that light can behave like a wave.

 

This video is on YouTube at https://youtu.be/kl5Cr04X1z4

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by Tony Wayne ...(If you are a teacher, please feel free to use these resources in your teaching.)