Speakers a and b are vibrating in phase. they are directly facing each other, are 8.2 m apart, and are each playing a 78.0 hz tone. the speed of sound is 343 m/s. on the line between the speakers there are three points where constructive interference occurs. what is the distance of the farthest point from speaker a?

6.298,4.1,1.9015

Explanation:

Wavelength=

==4.397 m

Distance of 3rd speaker from speaker A is x

From B 78-x

Difference between the distances must be a whole number of wavelengths

First

   for 1 st wavelength

2x=8.2+4.397=12.597

x=6.298m

second

For zero wavelength

2x=8.2

x=4.1m

Third

x=1.9015 m

6 cos 34, 6 sin 34 trig

which piece of furniture will have the most inertia and give the furniture movers the most difficulty in moving?  

answer

a 75kg dining table