Cosmic Velocity - First to Kilometer per Hour

The first cosmic velocity (escape velocity from Earth's surface to orbit) is approximately 7,900 m/s (7.9 km/s), the minimum speed needed to achieve Earth orbit.

v₁ = √(GM/r) where G is gravitational constant, M is Earth's mass, r is Earth's radius. Approximately 7.9 km/s.

To km/h: × 3,600. To mph: × 17,672. 7.9 km/s = 28,440 km/h = 17,672 mph.

Minimum speed for satellites, space station orbit, and low Earth orbit (LEO) calculations.

ISS orbits at ~7.66 km/s. Below this speed, you fall back to Earth. Above it, you stay in orbit (if horizontal).

Confusing with escape velocity (second cosmic velocity, 11.2 km/s) — orbital velocity is lower.

Remember: ~8 km/s for orbit, ~11 km/s to escape. v₁ is minimum for orbit, not escape.

Kilometer per hour measures the number of kilometers traveled in one hour. It's the most common speed unit for vehicles and everyday speed references in metric countries.

1 km/h = 1/3.6 m/s = 0.2778 m/s. There are 3600 seconds in an hour and 1000 meters in a kilometer.

To m/s: ÷ 3.6. To mph: × 0.621. To ft/s: × 0.911. To knots: × 0.540.

Speed limits (50 km/h urban, 100–130 km/h highway), vehicle speedometers, cycling speeds, marathon pace, and wind speed forecasts.

World's fastest train: 603 km/h (maglev). Commercial aircraft cruise: 850–950 km/h. Formula 1 top speed: 372 km/h. Hurricane winds: 119+ km/h.

Directly converting km to km/h without accounting for time. Also, confusing km/h with m/s in physics problems (always convert to SI).

Divide by 3.6 to convert to m/s. Quick approximation: 60 km/h ≈ 17 m/s. Remember: km/h ÷ 3.6 = m/s.