An underwater robot used in marine archaeclogy is immersed in seawater (density p; = 1025 kg_,-"m, bulk modulus B; = 2.37 x 10\" I\\',_.-"'m?]. This robot is equipped with a sonar that emits ultrasound at a frequency of 200 kHz with a pressure amplitude A,; = 179 Pa. When the ultrasound encounters an artifact (a stationary substance) with a bulk modulus B> = 10.34 x 1010 }Tm'2 and an impedance Z, > Z,the sonar-detected sound intensity level of the reflected waveis [ L, 99.2 dB. a) Calculate the impedance 2 and determine the sound intensity level 1 L.| with which the sonar emits. b) Calculate the impedance Z5 and the volumetric mass density p, of the artifact. c) What is the speed of ultrasound in the substance from which the artifact is made, and identify this substance from the following table: Substance Rubber Lead Concrete Gold Bronze Brass Iron Glass Granite Speed of TO 1905 3100 3240 3400 3508 4529 5300 G200 sound (m./s) d) If &1 = (), determine the wave function A.w' (:r._._ t_]l of the pressure acoustic wave reflected by the artifact. e) If the robot approaches the artifact and perceives a beat frequency of 292.5 Hz between the wave it emits and the echo it receives, determine the speed in km/h at which the robot is approaching the artifact