Shear Stress is defined as which of the following?

• A. Breakdown of material as the result of something sliding over two areas.
• B. Pulls and stretches the material.
• C. Pushes the material together.
• D. Causes twisting.

Answer: (A)

Shear stress is the internal force that happens when parallel forces act on a material and cause one layer to slide past another. This sliding changes the shape of the material without necessarily changing its overall length, and if the force is strong enough, the material can fail along the sliding planes. The option describes exactly that idea: material breaking down as a result of something sliding over two areas, which captures the idea of layers slipping past each other under shear.

The other ideas refer to different kinds of stress: pulling and stretching is tensile (stretching the material), pushing together is compressive (squeezing the material), and twisting relates to torsion (rotation that can create shear on internal planes but is not the general definition of shear stress).