Materials

Question 1

Breaking stress

Answer 1

The maximum stress that an object can withstand before failure occurs.

Question 2

Brittle

Answer 2

A brittle object will show very little strain before reaching it’s breaking stress

Question 3

Density

Answer 3

The mass per unit volume of a material

Question 4

Elastic limit

Answer 4

A force beyond which an object will no longer deform elastically, and instead deform plastically. Beyond the elastic limit, when deforming forces are removed, the object will no longer return to its original shape.

Question 5

Elastic Strain Energy

Answer 5

The energy stored in an object when it is stretched. It is equal to the work done to stretch the object and can be determined from the area under a force-extension graph.

Question 6

Hooke’s Law

Answer 6

The extension of an elastic object will be directly proportional to the force applied to it up to the limit of proportionality.

Question 7

Plastic behaviour

Answer 7

If a material deforms with plastic behaviour, it will not return to its original shape when the deforming forces are removed. The object will be permanently deformed.

Question 8

Spring constant

Answer 8

The constant proportionality for extension pf a spring under a force. The higher the spring constant, the greater force needed to achieve a given extension.

Question 9

Tensile strain

Answer 9

The ratio of an object’s extension to its original length. It is a ratio of two lengths so it has no unit.

Question 10

Tensile stress

Answer 10

The amount of force acting per unit area. Its unit is the Pascal (Pa)

Question 11

Young Modulus

Answer 11

The ratio of stress to strain for a given material. Its unit is the Pascal (Pa)