Convert Walking Speed (walk) to Cosmic Velocity - First (v₁) instantly.
About these units
Walking Speed (walk)
The average human walking speed is about 1.2–1.4 m/s (4–5 km/h), though this varies with fitness, terrain, age, and purpose. Walking is an energy-efficient mode of locomotion optimized through millions of years of evolution. Humans unconsciously adjust stride frequency, step length, and posture to maintain stability and minimize metabolic cost. Urban planning, pedestrian-safety engineering, and architecture all use walking-speed estimates to design sidewalks, crosswalk timing, and public transportation access. Walking speed is not merely a physical measure—it reflects physiology, psychology, and cultural context.
Cosmic Velocity - First (v₁)
The first cosmic velocity is the minimum horizontal speed an object must achieve to enter a stable orbit around a planetary body without additional propulsion. For Earth, this value is about 7.9 km/s. At this speed, an object's forward motion precisely balances with the gravitational pull downward, creating continuous free-fall—the essence of orbital motion. This velocity is foundational in orbital mechanics. Spacecraft reaching Low Earth Orbit (LEO) must achieve at least this horizontal speed, even if their vertical ascent profile varies. Understanding v₁ was essential in the early space age: it represented the threshold between atmospheric flight and true spaceflight, marking human entry into the orbital era.