How is strain defined in terms of deformation?

Strain is the measure of deformation in a material caused by an applied force.

When a force is applied to a material, it causes a change in its shape or size. Strain is the measure of this change in shape or size, and it is defined as the ratio of the change in length or size of the material to its original length or size. Strain is a dimensionless quantity, expressed as a percentage or a decimal.

There are two types of strain: tensile strain and compressive strain. Tensile strain occurs when a material is stretched, while compressive strain occurs when a material is compressed. The magnitude of strain depends on the magnitude of the applied force and the properties of the material, such as its Young's modulus.

Strain is an important concept in materials science and engineering, as it is used to predict the behaviour of materials under different conditions. For example, the strain in a bridge or a building can be calculated to ensure that it can withstand the forces acting on it. Strain is also used in the design of medical implants, such as artificial joints, to ensure that they do not cause excessive deformation in the surrounding tissue.