# Elasticity,stress, and strain questions

• defdek
In summary, the first conversation discusses the stretching of two metal rods with different cross-sectional areas when subjected to the same stretching force. The second conversation involves calculating the strain energy stored in an aluminium wire under tension, while the third conversation requires finding the Young's modulus and stress of a stretched wire based on its strain energy per unit volume.
defdek
1. A 3.0-mm2 cross sectional area metal rod is stretched by 0.4 mm when a certain stretching force is applied to it. Another rod of the same length and metal but of a cross sectional of twice as large is stretched by the same amount of force. Calculate the stretching in the second wire.

the answer is 0.2mm? half stretch than the first rod?

2.Compute the strain energy stored in an aluminium wire of 2.0 m long, 1.0 mm diameter subjected to a 25.0-N tension. [Y-aluminium = 7.0 x 10^10 Nm-2].
i just have to use this formula right?
F^2L/2AY

3.A stretched wire has strain energy per unit volume of 4.00 x 10^3 Jm-3. Find the Young’s modulus and the stress in the wire if the wire elongates 0.5% of its original length.
1/2Y(strain)^2 ?

Last edited:
(1) Excellent work, defdek. Your answer on question 1 is correct.

(2) Nice work on question 2. That is correct.

(3) <standing ovation. crowd roars.> Nice job on question 3. That is correct.

## 1. What is elasticity?

Elasticity refers to the property of a material that allows it to regain its original shape after being deformed or stretched.

## 2. How is stress defined?

Stress is defined as the force per unit area that is applied to a material, causing it to deform or change shape.

## 3. What is the relationship between stress and strain?

Stress and strain are directly proportional to each other, meaning that as stress increases, strain also increases. This relationship is known as Hooke's Law.

## 4. How is strain measured?

Strain is typically measured by the change in length of a material divided by its original length. It is often expressed as a percentage or decimal.

## 5. What factors affect the elasticity of a material?

The elasticity of a material can be affected by factors such as temperature, composition, and the amount of stress applied. Different materials also have varying levels of elasticity.

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