The first cosmic velocity (orbital velocity at Earth's surface) is approximately:
A9.8 km/s
B11.2 km/s
C7.9 km/s
D42 km/s
Answer & Solution
Correct answer: C. 7.9 km/s
v_orb = √(gR) ≈ 7.9 km/s for low Earth orbit. Note: v_esc = √2 × v_orb.
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