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Equation For Speed Of Sound

Speed of Sound Formula:

\[ v = \sqrt{\frac{\gamma P}{\rho}} \]

unitless
Pa
kg/m³
m/s

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1. What is the Speed of Sound Equation?

Definition: This equation calculates the speed at which sound waves propagate through a medium.

Purpose: It's essential in acoustics, aerodynamics, and various engineering applications where sound propagation is important.

2. How Does the Equation Work?

The equation is:

\[ v = \sqrt{\frac{\gamma P}{\rho}} \]

Where:

Explanation: The speed depends on how easily the medium can be compressed (γ), the pressure pushing molecules together (P), and how dense the molecules are (ρ).

3. Importance of Speed of Sound Calculation

Details: Understanding sound speed is crucial for designing acoustic systems, aircraft, and understanding atmospheric phenomena.

4. Using the Calculator

Tips: Enter the adiabatic index (default 1.4 for air), pressure (default 101325 Pa for standard atmosphere), and density (default 1.225 kg/m³ for air at sea level). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical adiabatic index for air?
A: For dry air at standard conditions, γ is approximately 1.4.

Q2: How does temperature affect sound speed?
A: Temperature affects density and pressure. For air, sound speed increases by about 0.6 m/s per °C rise.

Q3: What's the speed of sound in water?
A: About 1482 m/s at 20°C (using γ≈7, P≈varies, ρ≈998 kg/m³).

Q4: Why is γ unitless?
A: It's a ratio of two specific heat capacities (Cp/Cv), making the units cancel out.

Q5: Does this work for all gases?
A: Yes, but γ varies by gas (e.g., 1.67 for monatomic gases like argon, 1.3 for CO₂).

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