CHAPTER 6

Question 1

EXTENSION

Answer 1

the increase in length of an object when a tensile force is exerted on it

Question 2

TENSILE FORCES

Answer 2

equal and opposite forces acting on an material to stretch it

Question 3

COMPRESSIVE FORCE

Answer 3

two or more forces together that reduce the length or volume of an object

Question 4

COMPRESSION

Answer 4

the decrease in length of an object when a compressive force is exerted on it

Question 5

TENSILE DEFORMATION

Answer 5

a change in the shape of an object due to its tensile forces

Question 6

COMPRESSIVE DEFORMATION

Answer 6

a change in the shape of an object due to its compressive forces

Question 7

FORCE- EXTENSION GRAPH

Answer 7

a graph of force against extension, with the area under the graph equal to the work done on the material

Question 8

ELASTIC LIMIT

Answer 8

the value of stress or force beyond which elastic deformation becomes plastic deformation, and the material or object will no longer return to its original shape and size when the stress or force is removed

Question 9

ELASTIC DEFORMATION

Answer 9

a reversible change in the shape of an object due to a compressive or tensile force- removal of stress or force will return the object to its original shape and size

Question 10

HOOKES LAW

Answer 10

the force applied is directly proportional to the extension of of the spring unless the limit of proportionality is exceeded

Question 11

FORCE CONSTANT

Answer 11

a quantity determined by dividing force by extension for an object obeying hookes law- called constant of proportionality ‘k’, measured in Nm-1

Question 12

STIFFNESS

Answer 12

the ability of an object to restrict deformation

Question 13

ELASTIC POTENTIAL ENERGY

Answer 13

the energy stored in an object because of its deformation

Question 14

LOADING CURVE

Answer 14

a force- extension graph

Question 15

HYSTERESIS LOOP

Answer 15

a loop shaped plot obtained when loading and unloading a material produce different deformations

Question 16

TENSILE STRAIN

Answer 16

the extension per unit length

Question 17

TENSILE STRESS

Answer 17

the force per unit cross sectional area, measured in Pa

Question 18

DUCTILE

Answer 18

property of a material that has a large plastic region in a stress- strain graph, so can be drawn into wires

Question 19

LIMIT OF PROPORTIONALITY

Answer 19

the value of stress or force beyond which stress is no longer directly proportional to strain

Question 20

YIELD POINT

Answer 20

a point on a stress- strain graph beyond which the deformation is no longer entirely elastic

Question 21

ULTIMATE TENSILE STRENGTH

Answer 21

the maximum stress that a material can withstand before it breaks

Question 22

BRAKING STRENGTH

Answer 22

the stress value a the point of fracture, calculated by dividing the breaking force by the cross sectional area

Question 23

STRONG MATERIAL

Answer 23

a material with a large value for the ultimate tensile strength

Question 24

YOUNG MODULUS

Answer 24

the ratio of tensile stress to tensile strain when these quantities are directly proportional to each other, measured in Pa

Question 25

BRITTLE

Answer 25

property of a material that does not show plastic deformation and deforms very little under high stress

Question 26

POLYMERIC

Answer 26

description of a material comprising of long- chain molecules, such as rubber, which may show large strains