Practice question
Question
A satellite orbits at 3RE from Earth’s center. What is its speed? (g\=9.8m/s2,RE\=6.4×106m)
Explanation
v = gRE2r. r = 3RE, v = 9.8×6.4×1063. v = 2.09×107≈4.57×103m/s. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 4.6 × 10³ m/s. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.