Unformatted text preview: Physics 70 Spring 2010 ‘ ‘ First Name:
mstaieuersouasmame --- DL Section #; bgggrvcggggyggggggycggdgg Signature: 1 4m | 2 speaker #1 A speaker (speaker #1) is placed at one end of a long hallway. It plays a sound represented by the wave equation: P(:z:, t) = P0 + Asin (4007rt [l] + 7m: [—1—] + 1r). S m Clucky the Chicken is in the hallway facing this speaker and each of her ears is 4m away from the speaker. 1. Find the frequency U), the wavelengthm. and the speed (1;) of the sound in this hallway (don't forget your unitsl). 5.111915 m4 of? Jam Wm , _ l ' in)?
L’OOﬂ(3’ gel—4T 4) T’D—(TO 5 él‘pzaOQ/A? 51) TM a mi! WW?” 2. We want to keep Clucky from hearing the sound of speaker #1 without her knowing what we are doing. To do this we place a speaker
(speaker #2). which is hooked up to the same source. behind her where she can’t see it. The sound from speaker #1 completely cancels the
sound from speaker #2 so Clucky thinks the hall is almost perfectly silent. We have to keep speaker #2 at least 1m away from Clucky so she
doesn’t know it‘s there How far from Clucky should we place speaker #2 and what should its fixed phase constant be? Explain carefully how
your placement and phase keep Clucky from hearing any sound. “77% +051 (010% 9‘00”: 5W #l is T ,5} (jug-£55 pos‘i'oxi equations . ... ...
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- Spring '10