PHYS 121 Lecture Notes - Lecture 14: Sine Wave, Sound
16 Nov 2017
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Document Summary
If we suspend a stone at the end of a piece of string, we have a simple pendulum. The time of one to and fro swing is called the period. The longer the length of a pendulum, the longer the period (just as the higher you which a ball falls to the ground drop a ball from, the longer it takes to reach the ground) Wave -> periodic wiggle in space and time. Waves travel across grass on a windy day. A wave is pictorially represented by a sine curve. A sine curve is obtained when you trace out the path of a vibrating pendulum over time. When a bob vibrates up and down, a marking pen traces out a sine curve on the paper that moves horizontally at a constant speed. Distance from the midpoint to the top/bottom. Example: pendulum maes 2 vibrations in 1 second. frequency is 2 hz. period of vibration is 0. 5 seconds.
