An open organ pipe is $2.46 \mathrm{m}$ long, and the speed of the air in the pipe is $345 \mathrm{m} / \mathrm{s}$
a. What is the fundamental frequency of this pipe?
b. How many harmonics are possible in the normal hearing range, $20 \mathrm{Hz}$ to $20000 \mathrm{Hz}$ ?