Party hearing. As the number of people at a party increases, you must raise your voice for a listener to hear you against the background noise of the other partygoers. However, once you reach the level of yelling, the only way you can be heard is if you move closer to your listener, into the listener's "personal space." Model the situation by replacing you with an isotropic point source of fixed power Pand replacing your listener with a point that absorbs part of your sound waves. These points are initially separated by r; = 1.70 m. If the background noise increases by AB = 5.10 dB, the sound level at your listener must also increase. What separation r; is then required? Number i Units

In order to waken a sleeping child, the volume on an alarm clock is tripled. Under this new scenario, how much more energy will be striking the child’s ear drums each second?  a. twice as much b. three times as much c. approximately 4.8 times as much d. six times as much e. nine times as much

q8

Mechanical VWaves MCAS review 1. Which of the following statements describes the motion of air particles as a sound wave moves across a room? A. The air particles move in circles inside the sound wave. B. The air particles move across the room with the sound wave. C. The air particles move back and forth, parallel to the direction of the sound wave. D. The air particles move back and forth, perpendicular to the direction of the sound wave. 2. Which of the following types of waves is longitudinal? B. microwave A. light wave C. radio wave D,sound wave 3. The frequency of a note played on a piano is 262 Hz. Given that the velocity of sound at 20°C is 343 m/s, what is the wavelength of the note? A. 0.25 m B. 0.76 m C. 1.31 m D. 4.05 m 4. The table shows the speed of sound in various substances under different conditions. Speed (m/s) Temperature (°C) Substance State carbon dioxide 280 gas 51 methane 466 41 gas helium 972 gas ethanol 1144 liquid 25 water liquid 1461 liquid 1402 1 lubricating…

Q5: Answer the following: a. Name the two characteristics of vibration analysis. b. Amplitude can be measured by three ways, list them. c. List four conditions that can be determined by vibration analysis. d. Explain the uses and application of x-ray. e. Explain the uses and application of thermo graphic testing.

Q164 Jimmy is a researcher studying the sun. if jimmy knows that the intensity of the sunlight reaching the planet earth is 1.40 kW/m^(2), help jimmy find the following: a. What the power output of the sun is b. The intensity of the sunlight reaching the planet mercury

The wavelength of a microwave would be closest to the size of which of the following? a. A mountain b. A car c. A chicken d. A single celled organism

A12

A train whistle 2000 Hz sounds higher or lower in frequency depending on whether it approaches or recedes the observer. The difference between the two will be heard at the moment the train passes the observer. Calculate this difference for a train moving at a speed of 180 km/h. Take the speed of sound in air to be 330 m/s. State answer in hertz to the newest tenth of a hertz

A transformer is humming at a frequency of 6000 Hz and produces a standing wave in air. What is the distance between successive nodes? What is the distance between successive antinodes? If the speed of sound close to the standard value of 340 m/s.