Practice question
Question
An aluminium block of dimensions 0.6m×0.4m×0.2m is subjected to a shearing force of 8×104N. If the shear modulus of aluminium is 2.5×1010N/m2, what is the displacement of the top face?
Explanation
Shear modulus: G = F/AΔx/L. Rearrange: Δx = FLAG. Area: A = 0.6×0.4 = 0.24m2, L = 0.2m. Substitute: Δx = 8×104×0.20.24×2.5×1010 = 160006×109≈2.67×10−6m. As per NCERT, applying relevant law/formula with correct units and sign convention leads to 2.67×10−6m. This satisfies dimensional consistency and physical conditions given, so option B is scientifically correct.