A shear force is applied to a cube of glass, 10 cm on a side, such that the top of the cube is displaced sideways relative to the bottom. If the shear force is 10 000N, by how much does the top of the cube move relative to the bottom? The shear modulus of glass is 3x1010 N m-2.
A)0.33 μm.
B)1.0 μm.
C)3.3 μm.
D)10.0 μm.
E)33.3 μm.

Question

Quizplus · Accepted Answer

The shear strain is given by the formula: shear strain = shear stress / shear modulus. Shear stress is force/area, and the area is 0.1 m * 0.1 m = 0.01 m². Shear stress = 10,000 N / 0.01 m² = 1,000,000 N/m². Shear strain = 1,000,000 N/m² / 3x10¹⁰ N/m² = 3.33x10⁻⁵. The displacement is shear strain * original length = 3.33x10⁻⁵ * 0.1 m = 3.33x10⁻⁶ m = 3.3 μm.

A Shear Force Is Applied to a Cube of Glass