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Speed of Sound Equation:
Where v is in knots or mph, but calculated in m/s base
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The speed of sound equation v = 661.5 + 20T calculates the speed of sound in air based on temperature. This simplified formula is particularly useful in aviation applications where temperature variations significantly affect sound propagation.
The calculator uses the speed of sound equation:
Where:
Explanation: The equation shows that speed of sound increases with temperature at a rate of approximately 20 m/s per degree Celsius, starting from 661.5 m/s at 0°C.
Details: Accurate speed of sound calculations are crucial in aviation for Mach number determination, sonic boom prediction, aircraft performance calculations, and acoustic measurement corrections.
Tips: Enter temperature in degrees Celsius and select your preferred output unit (m/s, knots, or mph). The calculator will provide the speed of sound at that temperature.
Q1: Why does speed of sound change with temperature?
A: Sound travels faster in warmer air because molecules move more rapidly and transfer vibrational energy more efficiently.
Q2: What is Mach 1 at different temperatures?
A: Mach 1 equals the speed of sound, so it varies with temperature. At 15°C, Mach 1 is approximately 661.5 + (20×15) = 961.5 m/s or 1,870 knots.
Q3: How does humidity affect the speed of sound?
A: Humidity has a minor effect, increasing speed of sound slightly, but temperature is the dominant factor in the troposphere.
Q4: Why is this calculation important for aircraft?
A: Aircraft performance, especially near Mach 1, is highly sensitive to the actual speed of sound, which varies with atmospheric conditions.
Q5: How accurate is this simplified equation?
A: This linear approximation is reasonably accurate for typical aviation temperatures (-50°C to +50°C) with error typically less than 1%.