1. What is a Mach Number?

Definition: The Mach number is a dimensionless quantity representing the ratio of an object's speed to the speed of sound in the surrounding medium.

Purpose: It's used in aerodynamics to classify speed regimes (subsonic, transonic, supersonic, hypersonic) and predict compressibility effects.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( M \) — Mach number (dimensionless)
• \( v \) — Object speed (m/s)
• \( a \) — Speed of sound (m/s, ~343 at 20°C sea level)

Explanation: The object's speed is divided by the local speed of sound to determine how many times faster than sound the object is moving.

3. Importance of Mach Number

Details: Mach number is crucial in aircraft design, rocket science, and understanding shock waves. Different flow regimes occur at different Mach numbers.

4. Using the Calculator

Tips: Enter the object's speed in m/s and the local speed of sound (default 343 m/s for 20°C at sea level). Both values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What's the speed of sound at different altitudes?
A: The speed of sound decreases with altitude due to lower temperatures (~295 m/s at 10,000m).

Q2: What are typical Mach number ranges?
A: Subsonic (M < 0.8), Transonic (0.8-1.2), Supersonic (1.2-5.0), Hypersonic (M > 5.0).

Q3: How does temperature affect the calculation?
A: Speed of sound increases with temperature (a ≈ 331 + (0.6 × T°C) m/s).

Q4: What's Mach 1 in different units?
A: At sea level: ~343 m/s, ~1235 km/h, ~767 mph, ~1125 ft/s.

Q5: Why is Mach number important in aviation?
A: Critical for predicting shock waves, drag divergence, and structural stresses on aircraft.