Hookes Law

Plasticity

ability to be molded

stress formula

stress = force/area

shear stress

A measure of how easily a material can be twisted.

tensile strength

A measure of how much stress from pulling, or tension, a material can withstand before breaking.

Young's Modulus

A measure of the stiffness of an elastic material and defined by stress/strain.

Shear Modulus

A term describing a solid's resistance to shear stress, denoted by the letter S and measured by the ratio of shear stress (F/A) to strain (x/h).

what do the following letters stand for: F, K, x, W?

F: force K: spring constant / spring stiffness d or x: extension W: work done

Formula for Hooke's Law

F=kx k is the spring constant, units (Nm^-1)

Define Hooke's Law (2)

Hooke's Law states that the increase in length of a spring is directly proportional to the force pulling on it. If stretched beyond the elastic limit, the spring will not return to its original length.

what is extension measured in?

Metres (m)

What is force measured in?

Newtons

what is stress and strain?

Stress - force applied per unit area Strain - deformation produced by stress

Deformation/Strain

The amount of deformation produced is related to the stress caused by the focus and the material properties of the tissue that is loaded

how do you find the slope on a Hookes law graph?

difference in y / difference in x

yield point (elastic limit)

point on the load deformation curve past which deformation is permanent

Young's modulus formula

stress/strain

resilience

the amount of deformation required to bring a material to its elastic limit

elastic limit

the maximum extent to which a solid may be stretched without permanent alteration of size or shape.

rigidity

the physical property of being stiff and resisting bending

volume stress

the stress that causes bulk deformation