Materials

Question 1

What is the equation for density?

Answer 1

ρ = M / V

Question 2

What is the equation for elastic strain energy?

Answer 2

E = ½FΔL
E = ½Ke²

Question 3

How is the total spring constant calculated for springs in parallel?

Answer 3

kₜ = k₁+ k₂…

Question 4

How is the total spring constant calculated for springs in series?

Answer 4

1/kₜ = 1/k₁ + 1/k₂…

Question 5

What is Hooke’s law (equation)?

Answer 5

F = kΔL
or
F = ke

Question 6

What is Elasticity?

Answer 6

The ability of a solid to regain its shape after it has been deformed.

Question 7

What is Tensile Deformation?

Answer 7

The deformation of a solid due to stretching.

Change in shape of solid due to stretching force.

Question 8

What is Compression Deformation?

Answer 8

The deformation of a solid due to compression.

Change in shape of solid due to compressive force.

Question 9

What is ductility?

Answer 9

The ability to be drawn into wire, ductile materials have a very large plastic region.

Question 10

What is a brittle material?

Answer 10

Materials with little plastic deformation. Failure is sudden.

Question 11

What is stress?

Answer 11

The force per unit of cross-sectional area applied to a material.

Question 12

What is strain?

Answer 12

The change in length of a material over its original length.

Question 13

How is loading and unloading on a metal wire related (graph)?

Answer 13

The curve obtained during unloading follows parallel to the original curve.

Question 14

What is an alloy?

Answer 14

An alloy is a mixture of two or more metals.

Question 15

How do you calculate the density of an alloy with two metals?

Answer 15

ρ = (ρ₁V₁ + ρ₂V₂) / Vₜ

Question 16

What is Hooke’s Law?

Answer 16

A string’s extension is direct proportion to the force applied up until the elastic limit of the material.

Question 17

How do you calculate Young’s Modulus?

Answer 17

Stress / Strain

Question 18

What part of a stress-strain graph acts proportionally?

Answer 18

The elastic region of the material.

Question 19

What part of a stress-strain is the elastic region?

Answer 19

Where the graph acts proportionally.

Question 20

When a stress-strain graph begins to curve what does that point represent?

Answer 20

The elastic limit of the material.

Question 21

How is the elastic limit of a material represented on a stress-strain graph?

Answer 21

Where the graph begins to curve

Question 22

What is the name for the type of curve created by a force-extension graph of a wire?

Answer 22

Hysteresis curves

Question 23

What happens when a plastic material is stretched and then unstretched?

Answer 23

Tangled when unstretched with weak intermolecular forces between molecules.
These break during stretching but new bonds reform when the tension is removed.

Question 24

How is work done loading linked to work done unloading for a wire that follows Hooke’s Law?

Answer 24

The work done when loading = The work done when unloading

Question 25

How is energy lost due to deforming a wire calculated?

Answer 25

Energy Lost = Work Done Loading - Work Done Unloading

Question 26

What is the elastic limit of a material?

Answer 26

The point until which a material will return to its original shape when tension is withdrawn.

Question 27

What is the yield point of a material?

Answer 27

The point where there is a large permanent change in length with no extra load force.
The material starts to behave like a plastic.