Choosing the Right Material: Tensile Strength and Strain Calculations

Choosing the Right Material: Tensile Strength and Strain Calculations
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Slide 1: Slide
NatuurkundeMiddelbare schoolvwoLeerjaar 3

This lesson contains 25 slides, with interactive quizzes and text slides.

time-iconLesson duration is: 46 min

Items in this lesson

Choosing the Right Material: Tensile Strength and Strain Calculations

Slide 1 - Slide

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Learning Objectives
Being able to explain strain in simple words to a classmate
Reproduce and work with the formula for strain 
Being able to explain tensile stress in simple words to a classmate
Being able to explain elasticity
Being able to explain the difference between tensile stress and strain
 Reproduce and calculate with the formula for tensile strength

Slide 2 - Slide

Introduce the learning objectives and what students will be able to do by the end of the lesson.
Choosing the Right Material
When choosing a material for mountain climbing, lift cables, or hanging a painting, it's important to consider the material's properties.

Slide 3 - Slide

Explain how the concepts of tensile strength and strain can be applied to real-life scenarios.
mountainclimbing
lift
painting
Drag the cables to the pictures. Which cables would you use for what?

Slide 4 - Drag question

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What did you base your choices in the previous slide on?

Slide 5 - Open question

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What is Strain?
Strain is the measure of how much a material is stretched or compressed when a force is applied to it.

Formula: Strain (ε) = Change in length (Δl) / Original length (l)
ϵ=l0Δl

Slide 6 - Slide

Explain what strain is and how it is calculated.
Calculating Strain
Example
If we have an original length of 10 m and a change in length of 0.5 m, what is the strain? 
Data:


required:                                     ε

Workings:


 

ϵ=l0Δl
l0=10m
Δl=0.5m
ϵ=100.5
ϵ=0.05

Slide 7 - Slide

Provide an example for calculating strain to reinforce understanding.
What is the equation for calculating strain?
A
Δl=l0ϵ
B
ϵ=Δll0
C
l0=ϵΔl
D
ϵ=l0Δl

Slide 8 - Quiz

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If the original length is 8 m and the strain is 0.03, what is the change in length?
A
3.75 mm
B
8.03 m
C
24 cm
D
266.67 mm

Slide 9 - Quiz

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What is the original length if the strain is 0.0004 and the change in length is 0.2 cm?
A
5 m
B
16 m
C
24 m
D
8 m

Slide 10 - Quiz

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What is Tensile Strength?
Tensile strength is the maximum amount of stress a material can handle before it breaks or becomes deformed.

Slide 11 - Slide

Explain what tensile strength is and how it applies to different materials.
What is Tensile Stress?
Tensile stress is the amource distributed over the cross-sectional area.
So the force per square meter.
Formula:
σ=AF

Slide 12 - Slide

Explain what tensile strength is and how it applies to different materials.
Tensile Stress Formula
Formula:

       in Newton
       in 
        in            or Pa (Pascal)
σ=AF
F
A
m2
σ
m2N

Slide 13 - Slide

Explain what tensile strength is and how it applies to different materials.
What is the formula to calculate force for known tensile stress and cross-sectional area?
A
F=σA
B
F=σA
C
F=Aσ
D
F=σA

Slide 14 - Quiz

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What is the unit of tensile stress?
A
Liters
B
Volt
C
m2N
D
Meters

Slide 15 - Quiz

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What is NOT tensile stress?
A
Force distributed over cross-sectional area
B
The force per square inch
C
The force per square meter
D
Stress distributed over volume

Slide 16 - Quiz

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Formula for Tensile Strength
Tensile Strength (TS) = Force (F) / Cross-sectional area (A)


This is the same formula as for tensile stress, but it is the maximum stress tthe material can handle.

σ=AF

Slide 17 - Slide

Provide the formula for calculating tensile strength and explain how it is used.
Calculating Tensile Strength
If we have a force of 1000 N and a cross-sectional area of 5 m², what is the tensile strength?
 TS = F / A
TS =
 1000 N / 5 m²
TS = 200 N/m²

Slide 18 - Slide

Provide an example for calculating tensile strength to reinforce understanding.
Look up on the internet which material has the highest tensile strength?
A
Iron
B
Stainless steel
C
Human hair
D
Concrete

Slide 19 - Quiz

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Slide 20 - Slide

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Slide 21 - Open question

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Write down 3 things you learned in this lesson.

Slide 22 - Open question

Have students enter three things they learned in this lesson. With this they can indicate their own learning efficiency of this lesson.
Write down 2 things you want to know more about.

Slide 23 - Open question

Here, students enter two things they would like to know more about. This not only increases involvement, but also gives them more ownership.
Ask 1 question about something you haven't quite understood yet.

Slide 24 - Open question

The students indicate here (in question form) with which part of the material they still have difficulty. For the teacher, this not only provides insight into the extent to which the students understand/master the material, but also a good starting point for the next lesson.

Slide 25 - Slide

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