Practice question
Question
What is the kinetic energy of a 900kg satellite at 11RE from Earth’s center? (ME\=6×1024kg,RE\=6.4×106m,G\=6.67×10−11N m2/kg2)
Explanation
K = GMEm2r. r = 11RE = 7.04×107m. K = 6.67×10−11×6×1024×9002×7.04×107. K = 3.602×10171.408×108≈2.56×109J. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 2.6 × 10⁹ J. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.