1. What is the Average Speed Formula?

Definition: This calculator computes the average speed when two different speeds are maintained over equal distances.

Purpose: It helps determine the true average speed when travel speeds vary, which is different from a simple arithmetic mean.

2. How Does the Calculator Work?

The calculator uses the harmonic mean formula:

Where:

• \( AS \) — Average speed (mph)
• \( S1 \) — First speed (mph)
• \( S2 \) — Second speed (mph)

Explanation: This formula accounts for the fact that more time is spent traveling at the lower speed when covering equal distances.

3. Importance of Correct Average Speed Calculation

Details: Using the harmonic mean gives accurate travel time estimates, fuel consumption calculations, and trip planning.

4. Using the Calculator

Tips: Enter both speeds in mph. The calculator works for any speed units as long as both inputs use the same unit.

5. Frequently Asked Questions (FAQ)

Q1: Why not just average the two speeds?
A: A simple average assumes equal time at each speed, while this formula accounts for equal distances at each speed.

Q2: Does this work for more than two speeds?
A: For n speeds, the general harmonic mean formula is \( AS = \frac{n}{\frac{1}{S1} + \frac{1}{S2} + ... + \frac{1}{Sn}} \).

Q3: What if I traveled different distances at each speed?
A: Then you would use a weighted harmonic mean based on the distances traveled.

Q4: Can I use km/h instead of mph?
A: Yes, as long as both speeds use the same units, the result will be in those units.

Q5: What's a practical example of this calculation?
A: If you drive 60 mph to a destination and 40 mph back (same distance), your average speed is 48 mph, not 50 mph.