Practice question

Given: An aluminium block of dimensions 0.4 m × 0.2 m × 0.05 m is subjected to a shearing force of 2 × 10⁴ N . If the shear modulus of aluminium is 2.5 × 10¹⁰ N/m², what is the displacement of the top face? These values define the system as per NCERT data. Formula: Shear modulus: G = F / A/Δ x / L. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: Rearrange: Δ x = F L/A G . Area: A = 0.4 × 0.2 = 0.08 m², L = 0.05 m . Substitute: Δ x = frac2 × 10⁴ × 0.050.08 × 2.5 × 10¹⁰= 1000/2 × 10⁹= 5 × 10⁻⁷ m . Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.