8.03 - Lect 2 - Beats, Damped Free Ocillations, Quality Q

i will start today with a very interesting phenomenon which is known as beat phenomenon suppose you have two simple harmonic motions with the same amplitude but with different frequencies so we have x1=Acosw1t and you have x2=Acosw2t , and the two are different same amplitude If you sum them, X1 plus X2, you get 2A times the cosine of half the sum omega one plus omega two divided by two times T times the cosine of half the difference. And, when you look at this, you have here a frequency which is high compared to this frequency You can best see that if omega one is very close to omega two. You can simply replace that by omega Then this is simply saying cosine (omega t) And so, if you change from the notation of omega you have to frequency in hertz which is a lot easi er to think of Omega= 2 pi times the frequency f This is in hertz, this is in rad/sec Suppose you have

Channel: Lectures by Walter Lewin. They will make you ♥ Physics.

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Keywords: Walter Lewin, Physics, Beats, Damped Oscillations, Quality Q, High Resolution, Tortional Pendulum

Id: pnfZjGIyKVw

Length: 80min 52sec (4852 seconds)

Published: Tue Feb 10 2015