Two strings which are fixed at both ends are identical except that one is 0.65 cm longer than the other. Waves on both of these string propagate with a speed of 34.9 m/sec and the fundamental frequency of the shorter string is 220 Hz. a) What is frequency of the beat that would result if these two strings were plucked at the same time? For this, I did 34.9 / 220 to get the length of the string, which was 0.158636m. Then I added 0.065m to it to get 0.2236m. Then I did, 34.9 / 0.2236 to get the new frequency which is 156.0569 Hz, but thats not right. It makes sense since the new frequency should be greater. What am I doing wrong? c) What is the beat frequency if the length difference is now 0.8 cm? For this one, I would pretty much follow the same steps for part a, but use 0.08m and then subtract 220 from this new frequency.