lec27-print

# lec27-print - In reality there are two major categories of...

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In reality, there are two major categories of waves: Mechanical Waves (UPI), which require a medium of some sort, such as air, water or a slinky or string. (Sound, water waves, waves on a string or a slinky.) Electromagnetic Waves (UPII) or gravitational waves (grad school) are waves supported by a “field” or fields. They require no medium and always travel at the speed of light. (Radio, TV, cell phone signals, etc., are all electromagnetic waves.) There are many analogies between these. 17.1 Representation of Waves Mechanical waves require a medium to propagate along or through and involve the displacement of particles. The medium for sound waves is the air. Understand the difference between transverse and longitudinal waves. Mechanical waves can be classified into two types: transverse and longitudinal. Transverse waves cause a displacement of the material in the medium that is perpendicular to the direction of propagation. (It is the direction of momentum carried as well.) Example: A water wave is an example of a transverse wave. As the water wave propagates, we see the water rise and fall, but it does not move in the direction the wave travels (If you don't believe this, look at what happens to a leaf floating on the surface of a swimming pool when a wave reaches it. You will notice that it just moves up and down). This is only when the depth of the water is about constant. When waves roll into the shore, this is a different effect! Longitudinal waves cause a displacement of the material in the medium that is parallel to the direction of travel. Example: Whenever you displace one end of a spring and let go, you get a longitudinal wave

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lec27-print - In reality there are two major categories of...

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