Practice question
Question
What is the kinetic energy of a 800kg satellite at 10RE from Earth’s center? (ME\=6×1024kg,RE\=6.4×106m,G\=6.67×10−11N m2/kg2)
Explanation
K = GMEm2r. r = 10RE = 6.4×107m. K = 6.67×10−11×6×1024×8002×6.4×107. K = 3.202×10171.28×108≈2.50×109J. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 2.5 × 10⁹ J. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.