Problem 4.170

Find the number of possible natural oscillations of air column in a pipe whose frequencies lie below $v_{0}=1250 \mathrm{~Hz} .$ The length of the pipe is $l=85 \mathrm{~cm} .$ The velocity of sound is $v=340 \mathrm{~m} / \mathrm{s}$. Consider the two cases: (a) the pipe is closed from one end; (b) the pipe is opened from both ends. The open ends of the pipe are assumed to be the antinodes of displacement.