A. A tachymeter can be used to measure the time (within 60 seconds) that it takes to cover one kilometer, and then use that result to determine the approximate average (hourly) speed.
1. Start elapsed time measurement with the stopwatch.
2. Stop the stopwatch operation after a distance of one kilometer is covered. The value on the outside periphery of the bezel that the second hand is pointing to is your average speed. For example, if it takes you 30 seconds to cover one kilometer, the second hand will be pointing to 120. This indicates that your average speed is 120 km/h.
The outer tachymeter values indicate average speed based on the time it takes to cover one kilometer. If you cover two kilometers, double the indicated value to calculate the average speed. If you cover only 500 meters (half a kilometer), divide the indicated value by two to calculate the average speed.