A speedboat, starting from rest, moves along a straight line

A speedboat, starting from rest, moves along a straight line away from a dock. The boat has a constant acceleration of 13.00 m/s2 (see the figure). Attached to the dock is a siren that is producing a 755-Hz tone. If the air temperature is 20 °C, what is the frequency of the sound heard by a person on the boat when the boat's displacement from the dock is + 45.0 m?

A speedboat, starting from rest, moves along a straight line