satellites (orbital speed)

Question

Orbital speed of satellite just above Earth's surface (radius R) is approximately:

RankGuru · Accepted Answer

For a satellite in circular orbit, the gravitational force provides the centripetal force:
$\frac{GMm}{R^2} = \frac{m v^2}{R} \implies v = \sqrt{\frac{GM}{R}}$
Since $g = \frac{GM}{R^2}$, we can write $GM = gR^2$.
Substituting: $v = \sqrt{\frac{gR^2}{R}} = \sqrt{gR}$.
- For Earth, $v_{orbital} \approx 7.9 	ext{ km/s}$.

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satellites (orbital speed)

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