Properties of Waves from Graphs

by Patrick Ford
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Hey, guys, let's do a quick example about waves. What are the properties of the following wave Wave length, period, frequency and speed given in the graphs. Okay, so we have two graphs. We have a sorry, a displacement versus position and a displacement versus time graph. OK, Displacement versus position is gonna tell us things about distances and displacement versus time is gonna tell us things about time now going from peak toe peak, we could define one cycle. The distance that one cycle takes is the wavelength. But we're Onley given half that distance right from a peak to a trough is one half of the wavelength. So we can say one half of the wavelength is two centimeters. Which means that the wavelength is just four centimeters. Right, Double that easy now. The peak to the peak on the time graph will give us the period in that time, as we're shown, is five seconds. So we know that the period is five seconds. Okay, so we know the wavelength and the period. Now we need to find the frequency, the frequency we confined from the period. Really easy. We could just say the frequency is one over the period, which is 1/5 seconds, which is 0.2 hurts. Okay, very easy. Let me give myself just a little bit of space. We know the frequency now, and finally we want to know the speed. The speed equation can either be the wavelength over the period. Or it could be the wavelength times the frequency. It doesn't matter which one you use since you know all three of these pieces of information, but I'll just use for centimeters times 30. seconds, which is 0.8 centimeters per second. And that's the speed. All right. Thanks for watching guys.