a. An organ pipe open at both ends has a fundamental frequency of 400 Hz. If one end of this pipe is now closed, what will the new fundamental frequency be? [3] b. A transverse harmonic wave with a frequency of 80 Hz and an amplitude of 0.025 m travels along a string to the left with a propagation speed of 12 m/s. The mass of the string is 617mg. i. Write down a suitable (explicit) wave equation that best describes this wave. [3] ii. Find the maximum vertical speed of a point on the string. [3]