3. A noise created by small earthquake at a depth of 1200 m in the ocean propagates upward and eventually reaches a bird flying above, at an altitude of 400 m. Calculate how long it takes for the noise to reach the bird. For the seawater use E = 2.34 x 10°N/m², p=1030 kg/m^3, and for air, y = 1.4, and T=270°K).

Fig: 1

Fig: 2