Kilometer per hour (km/h)
The kilometer per hour, symbol km/h, measures speed based on metric distance over time. It became widely used in Europe in the 19th century as road travel and railways expanded, providing a convenient unit for vehicle speed. One kilometer per hour equals 1000 meters traveled in one hour. Today, it is the standard speed unit for road traffic, navigation systems, and weather reporting in most countries, except a few that use miles per hour. Kilometers per hour offers an intuitive way to understand everyday speeds while maintaining metric consistency with distance and time measurements.
Foot per second (ft/s)
The foot per second, symbol ft/s, is an imperial unit of speed representing how many feet an object travels in one second. It originated in English engineering and physics as a practical unit for measuring velocities on land and in laboratory settings. One ft/s equals 0.3048 meters per second. While less common in everyday applications compared to mph, it is still used in scientific experiments, ballistics, and technical specifications in the United States. The unit bridges imperial measurements with precise, time-based speed calculations.