1. What is Doppler Speed?

The Doppler speed measures the relative velocity between a wave source and observer. It's based on the Doppler effect, which describes how wave frequency changes when there's relative motion between source and observer.

2. How Does the Calculator Work?

The calculator uses the Doppler equation:

Where:

• \( v \) — Doppler speed (m/s)
• \( c \) — Speed of light (3 × 10⁸ m/s)
• \( f_o \) — Observed frequency (Hz)
• \( f_s \) — Source frequency (Hz)

Explanation: The equation calculates the relative velocity based on the frequency shift between the emitted and observed waves.

3. Importance of Doppler Speed Calculation

Details: Doppler speed calculations are crucial in radar systems, astronomical observations, medical ultrasound, and speed measurement applications.

4. Using the Calculator

Tips: Enter both frequencies in Hz. The source frequency must be greater than zero. Positive results indicate approaching objects, negative results indicate receding objects.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between Doppler speed and regular speed?
A: Doppler speed specifically measures relative velocity based on frequency shifts, while regular speed is absolute velocity.

Q2: Can this be used for sound waves?
A: This calculator uses the speed of light. For sound, you'd need to replace c with the speed of sound (343 m/s in air at 20°C).

Q3: What causes negative Doppler speeds?
A: Negative values occur when the observed frequency is lower than the source frequency (redshift), indicating the object is moving away.

Q4: How accurate is Doppler speed measurement?
A: Accuracy depends on precise frequency measurement. Small frequency differences can result in large speed differences at high velocities.

Q5: What are common applications?
A: Used in police radar guns, weather radar, astronomy (measuring star velocities), and medical Doppler ultrasound.