1. What is the Speed of Sound Equation?

The speed of sound in air varies with temperature and can be calculated at different altitudes using the atmospheric lapse rate. This calculator provides the speed of sound based on standard atmospheric conditions.

2. How Does the Calculator Work?

The calculator uses these equations:

Where:

• \( v \) — Speed of sound (m/s)
• \( \gamma \) — Adiabatic index (1.4 for dry air)
• \( R \) — Specific gas constant for air (287 J/kg·K)
• \( T \) — Temperature at altitude (K)
• \( T_0 \) — Sea level standard temperature (288 K)
• \( L \) — Temperature lapse rate (0.0065 K/m)
• \( h \) — Altitude above sea level (m)

Explanation: The speed of sound increases with temperature. As altitude increases, temperature typically decreases, reducing the speed of sound.

3. Importance of Speed of Sound Calculation

Details: The speed of sound is crucial in aerodynamics, aviation, meteorology, and acoustics. It affects aircraft performance, Mach number calculations, and sound propagation.

4. Using the Calculator

Tips: Enter altitude in meters, adiabatic index (1.4 for dry air), sea level temperature (288 K standard), and lapse rate (0.0065 K/m standard). All values must be valid positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: Why does speed of sound change with altitude?
A: The speed depends on temperature, which decreases with altitude in the troposphere (up to about 11 km).

Q2: What is the standard speed of sound at sea level?
A: About 343 m/s (761 mph or 661 knots) at 20°C (293 K).

Q3: How does humidity affect the speed of sound?
A: Increased humidity slightly increases the speed (about 0.1-0.2% at normal conditions).

Q4: What happens in the stratosphere?
A: Above the tropopause, temperature becomes constant or increases, changing the speed-altitude relationship.

Q5: How accurate is this calculator?
A: It provides theoretical values for standard conditions. Actual atmospheric conditions may vary.