Final answer:
Deformation is a change in the shape or size of an object due to stress, which encompasses tensile, compressive, bulk, or shear stress. It is a key concept in the field of physics, especially when discussing the properties of materials under different forces.
Step-by-step explanation:
Deformation is any change in shape or size of a body when stress is applied to it. This stress can be due to various forces, such as tensile, compressive, bulk, or shear forces, and the resulting deformation is called strain. Stress is quantified as the force per unit area exerted on a body, leading to deformation such as stretching, compressing, bending, or twisting. Different types of stress include tensile stress (elongation), compressive stress (compression), bulk stress (volume change), and shear stress (tangential deformation). Bulk stress is notable as it is experienced as pressure when submerged in a fluid, always acting perpendicular to the object's surface and tending to reduce its volume. Generally, the force and the deformation it causes are proportional for small deformations, which applies to changes in length, sideways bending, and changes in volume. Experiments have shown that biological materials like cells and tissues can exhibit elastic behavior in response to stress over certain timescales.