(Solved): A student holds a tuning fork oscillating at 256Hz. He walks toward a wall at a constant speed of ...

A student holds a tuning fork oscillating at $256\mathrm{Hz}$. He walks toward a wall at a constant speed of $1.52\mathrm{m}/\mathrm{s}$. (a) What beat frequency does he observe between the tuning fork and its echo? $\mathrm{Hz}$ (b) How fast must he walk away from the wall to observe a beat frequency of $4.40\mathrm{Hz}$ ? $\mathrm{m}/\mathrm{s}$