A foghorn that emits a frequency of \(150 \mathrm{~Hz}\) is mounted on a buoy in the bay. If a ship approaches the buoy at \(21.2 \mathrm{~km} / \mathrm{h},\)

(a) what frequency does the captain of the ship hear?

(b) Hearing the foghorn is a signal for the captain to slow his ship. After passing the buoy, the captain hears the horn again, but the frequency he detects is now \(149 \mathrm{~Hz}\). What is the new speed of the ship?