Deformation of solids

Question 1

What is the elasticity of a material?

Answer 1

its ability to regain its shape after it has been deformed or distorted and the forces that deformed it have been released

Question 2

what is the name given to deformation that streches and object and compresses an object?

Answer 2

stretches - tensile

compresses - compressive

Question 3

How is tensile strength tested?

Answer 3

material is loaded with hanging weights

ruler used to measure the extension

results can be plotted as a tension / extension graph

Question 4

What is the difference between elastic and plastic?

Answer 4

elastic - returns to original shape

plastic - stays in new shape

Question 5

what is the difference between ductile and malleable?

Answer 5

ductile - can be drawn into wires

malleable - can be hammered into sheets

Question 6

what is the difference between tough and brittle?

Answer 6

tough - can absorb a lot of energy before it breaks (area under stress/strain curve)

brittle - cannot deform plasticly, does not absorb a lot of energy before it breaks

Question 7

What does a steel spring give on a tension - extension graph?

Answer 7

a straight line through the origin

Question 8

what type of curve does a rubber-band give on tension-extension graph?

Answer 8

first extends easily when it is strethced

it becomes fully stretched and very difficult to stretch further when it has considerably been lengthened

Question 9

What curve does a polythene strip give?

Answer 9

stretches easily after its initial stiffness is overcame

however, after ‘giving’ easily, it extends little becomes difficult to stretch