An undersea explosion occurs. If the sea water has density 1.03 x 10³ kg/m3 and Bulk Modulus of 2.41x10⁹ Nm^-2 ;

a)  Determine the velocity of sound in sea water

b)  If the acoustic power released by the explosion is modelled as a continuous 180 kW (for the brief duration of the explosion) determine the distance that an observer would have to be from the explosion for the sound to be just at the "threshold of pain" (1 Wm^-2). You may model the distribution of sound energy as "Isotropic".

c)  Determine the sound pressure level in dB at a distance of 1 km from the explosion site.

d) Determine the change in frequency of the 50 Hz component of the explosions complex sound waveform that would be heard by an observer moving at 20 ms^-1 directly away from the site of the explosion.