Practice question
Question
What is the kinetic energy of a 150kg satellite at 3RE from Earth’s center? (ME\=6×1024kg,RE\=6.4×106m,G\=6.67×10−11N m2/kg2)
Explanation
K = GMEm2r. r = 3RE = 1.92×107m. K = 6.67×10−11×6×1024×1502×1.92×107. K = 6.003×10163.84×107≈1.56×109J. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 1.6 × 10⁹ J. This satisfies dimensional consistency and physical conditions given, so option C is scientifically correct.