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  2. Speed of sound - Wikipedia

    en.wikipedia.org/wiki/Speed_of_sound

    The speed of sound (blue) depends only on the complicated temperature variation at altitude and can be calculated from it since isolated density and pressure effects on the speed of sound cancel each other. The speed of sound increases with height in two regions of the stratosphere and thermosphere, due to heating effects in these regions.

  3. Moody's Corporation - Wikipedia

    en.wikipedia.org/wiki/Moody's_Corporation

    Moody's was founded by John Moody in 1909 to produce manuals of statistics related to stocks and bonds and bond ratings. Moody's was acquired by Dun & Bradstreet in 1962. In 2000, Dun & Bradstreet spun off Moody's Corporation as a separate company that was listed on the NYSE under MCO.

  4. Blackmer RMS detector - Wikipedia

    en.wikipedia.org/wiki/Blackmer_RMS_detector

    Unlike peak value or average value, RMS is directly related to energy, being equivalent to the direct current that would be required to get the same heating effect. In audio applications, RMS is the only metric directly related to perceived loudness, being insensitive to the phase of harmonics in complex waveforms. [6] Magnetic recording and ...

  5. Johnson–Nyquist noise - Wikipedia

    en.wikipedia.org/wiki/Johnson–Nyquist_noise

    A resistor with thermal noise can be represented by its Thévenin equivalent circuit (Figure 4B) consisting of a noiseless resistor in series with a gaussian noise voltage source with the above RMS voltage. Around room temperature, 3 kΩ provides almost one microvolt of RMS noise over 20 kHz (the human hearing range) and 60 Ω·Hz for ...

  6. Thermal velocity - Wikipedia

    en.wikipedia.org/wiki/Thermal_velocity

    Thus, indirectly, thermal velocity is a measure of temperature. Technically speaking, it is a measure of the width of the peak in the Maxwell–Boltzmann particle velocity distribution . Note that in the strictest sense thermal velocity is not a velocity , since velocity usually describes a vector rather than simply a scalar speed .

  7. Sound - Wikipedia

    en.wikipedia.org/wiki/Sound

    Those physical properties and the speed of sound change with ambient conditions. For example, the speed of sound in gases depends on temperature. In 20 °C (68 °F) air at sea level, the speed of sound is approximately 343 m/s (1,230 km/h; 767 mph) using the formula v [m/s] = 331 + 0.6 T [°C].

  8. Underwater acoustics - Wikipedia

    en.wikipedia.org/wiki/Underwater_acoustics

    The speed of sound (i.e., the longitudinal motion of wavefronts) is related to frequency and wavelength of a wave by =.. This is different from the particle velocity , which refers to the motion of molecules in the medium due to the sound, and relates to the plane wave pressure to the fluid density and sound speed by =.

  9. Kinetic theory of gases - Wikipedia

    en.wikipedia.org/wiki/Kinetic_theory_of_gases

    The temperature of the ideal gas is proportional to the average kinetic energy of its particles. The size of helium atoms relative to their spacing is shown to scale under 1,950 atmospheres of pressure. The atoms have an average speed relative to their size slowed down here two trillion fold from that at room temperature.