Practice question
Question
Three masses of 18kg each form an equilateral triangle with side 12m. What is the net force on one mass? (G\=6.67×10−11N m2/kg2)
Explanation
Force between two masses: F = Gm2r2 = 6.67×10−1118×18122 = 1.50×10−10N. Two forces at 60°: FR = F2+F2+2F2cos60∘. FR = (1.50×10−10)2(1+1+1) = 1.50×10−103. FR≈2.60×10−10N. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 2.6 × 10⁻¹⁰ N. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.