Understanding air particle velocity as cross product freq x dispby The_Lobster Tags: cross product, math, particle velocity, sound 

#1
Apr1712, 05:20 AM

P: 30

I'm reading a book on microphones and came across the following:
I feel stupid for asking this, but I don't get how the above equation works? For one, I thought cross products could only be be involving vectors? Aren't all the terms above scalars? Should I treat it as a dot product? Any help in understanding the above, so I can see how the terms affect each other is greatly appreciated! 



#2
Apr1712, 05:55 AM

Engineering
Sci Advisor
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Thanks
P: 6,385

I don't think it is a cross product. It looks like the standard equation for velocity of a particle moving in simple harmonic motion.
I don't know why the book used ##\times## as a multiplication sign here. 



#3
Apr1712, 05:59 AM

P: 30

Thanks, AlephZero! Typical of me getting thrown off by poor notation...




#4
Apr1712, 06:06 AM

P: 30

Understanding air particle velocity as cross product freq x disp
AlephZero: Are you saying that that equation is pretty much: [itex] v =  A\omega \sin \omega t [/itex]? Does that mean I can consider the "maximum particle displacement" in the first equation, as the amplitude, A?



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