108. ••Medical An ultrasonic scan uses the echo waves coming from something moving (such as the beating heart of a fetus) inside the body and the waves that are directly received from the transmitter to form a measurable beat frequency. This allows the speed of the internal structure to be isolated and analyzed. What is the beat frequency

71. •TWO identical speakers (1 and 2) are playing a tone with a frequency of 171.5 Hz, in phase (Figure 13-42). The speakers are located 6 m apart. Determine what points (A, B, C, D, or E, all separated by 1 m) will experience constructive interference along the line that is 6 m in front of the speakers. Point A is directly in front of speaker 1. The speed of sound is 343 m/s for this problem. SSM 6 m 1 6 m А В CD E

True or False; if false, please explain why a) There are three classifications to damping: Overdamped, Critically damped, and Superdampedb) A system that is critically damped will return to rest faster than the same system when overdamped.c) Completely undamped simple harmonic motion is quite rare in the real world.d) A RLC series circuit is mathematically identical to a damped spring-mass oscillator.

Ultrasound• Define acoustic impedance and intensity reflection coefficient.• Describe medical and other uses of ultrasound technology.• Calculate acoustic impedance using density values and the speed of ultrasound.                                                                                                            • Calculate the velocity of a moving object using Doppler-shifted ultrasound.

•30 The source of a sound wave has a power of 1.00 µW. If it is a point source, (a) what is the intensity 3.00 m away and (b) what is the sound level in decibels at that distance?