Stress (mechanics)
In physics, the stress at a point in a material is the limit for small areas of the force per unit area. Material properties are often given in terms of stress. For instance, a steel bolt may be made from a steel who's yield stress is 100 MPa. If the bolt's cross-sectional area is 500 μm2, it can be expected to fail at around 50 KN load. Another bolt made of the same material, but with half the diameter would fail at around 125 KN.