Q 11-07-036NEETJEE MainMedium
The height of a geostationary satellite above the Earth's surface is about $36000$ km. Taking the Earth's radius as $6400$ km, the orbital speed of such a satellite is about
Answer: (D) $3.1$ km/s
Concept. $v = \dfrac{2\pi r}{T}$ with $T = 24$ h.
Step 1. Radius. $r = 42400$ km.
Step 2. Speed. $\dfrac{2\pi \times 42400}{86400} \approx 3.1$ km/s.
Answer. $3.1$ km/s (Option D).
Solution by Sreeraj P, M.Sc Physics