Cosmic Velocity - Second to Yard per Second

The second cosmic velocity (Earth's escape velocity) is approximately 11,200 m/s (11.2 km/s), the minimum speed to escape Earth's gravity completely.

v₂ = √(2GM/r) = √2 × v₁ ≈ 11.2 km/s. Exactly √2 times the first cosmic velocity.

To km/h: × 3,600. To mph: × 25,000. 11.2 km/s = 40,320 km/h = 25,053 mph.

Moon missions, Mars missions, deep space probes (Voyager, New Horizons), and any mission leaving Earth's gravity well.

Apollo missions: ~11.2 km/s. Voyager probes: exceeded v₂ to leave solar system. New Horizons: launched at record 16.26 km/s (fastest ever from Earth).

Thinking you need this speed everywhere — you only need it at launch. In space, much less Δv is needed.

~11 km/s to escape Earth. √2 × orbital velocity. Remember: orbit ≈ 8 km/s, escape ≈ 11 km/s.

Yard per second measures distance in yards traveled in one second.

1 yd/s = 0.9144 m/s = 3.29 km/h = 2.045 mph = 3 ft/s.

To ft/s: × 3. To m/s: × 0.9144. To mph: × 2.045.

Sprint speeds in track and field (10–12 yd/s for elite sprinters), projectile velocities, and some fluid flow measurements.

Usain Bolt peak: ~13.5 yd/s. NFL wide receiver sprint: ~11 yd/s. Baseball thrown: ~40–45 yd/s.

Confusing with ft/s — yd/s is 3× faster. Mixing up with mph.

1 yd/s = 3 ft/s = 0.9144 m/s. Multiply by ~2 to get approximate mph.