Practice question
Question
A body weighs 343N on Earth’s surface. What is its weight at a height h\=RE/5? (g\=9.8m/s2)
Explanation
g(h) = g(1+h/RE)2. h = RE/5, 1+h/RE = 1+1/5 = 6/5. g(h) = 9.8(6/5)2 = 9.8×2536 = 6.81m/s2. Mass: m = 343/9.8 = 35kg. Weight: W = 35×6.81≈238N. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 238 N. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.