Aspeaker fixed to a moving platform moves toward a wall, emitting a steady sound with a frequency of 245 hz. a person on the platform right next to the speaker detects the sound waves reflected off the wall and those emitted by the speaker.
how fast should the platform move, vp, for the person to detect a beat frequency of 3.00 hz?
i think it’s d-decreases the amount of work.
in spring mass system we know that angular frequency is given as
f = 8.38 hz
now we know that speed of shm at its extreme position is given by
here we know that
a = 17.5 cm
so maximum speed is 9.21 m/s
constructive interference in which waves strengthen each other
- costructive interference occurs when two (or more) waves meet each other in phase, so with same displacement at the same point. in such situation, the two waves strengthen each other, and the amplitude of the resultant wave is the sum of the amplitudes of the individual waves
- destructive interference occurs when two waves meet each other in anti-phase, so with opposite displacement at the same point. in such situation, the two waves cancel each other out, and the amplitude of the resultant wave is the difference of the amplitudes of the individual waves (which means zero if the two waves are identical)
for light waves interfering with each other, 'white' means costructive interference, while 'black' means destructive interference (because black is absence of colors, so this means that the waves cancel each other out). in this problem, we see that point x, y and x are white, therefore they are point of constructive interference, where the waves strengthen each other.