What is the correct calculation for the Young's modulus using Hooke's Law?

In summary, the conversation discusses a student's difficulty in getting the correct answer for a question about Hooke's Law. They mention the equation E=kL/A and the values for k, L, and A. After some discussion about units and conversions, the student is able to get a more reasonable answer.
  • #1
groom03
27
0
[SOLVED] More hookes law question

Homework Statement


i can't get the equation to work out to the right answer of 110-130Gpa



Homework Equations


E=kL/A

k-1.45
L=2metres
A = 0.292cm


The Attempt at a Solution



i get 0.0099Gpa
 
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  • #2
Can you please post the question and how you got your answer? How is anyone supposed to help you if we don't know your question or how you got to your answer?
 
  • #3
Sorry.

I've got to work out the Youngs modulus of a meterial using the equation k=EA/L which rearrnged to E=kL/A i know k because its the gradient of a force extension graph i made, A is the x-sectional area of the wire and L is original length of the wire. wiki says the youngs modulus of copper 110-130 Giga Pascals but i get something stupid like 0.009Gpa.
 
  • #4
Hmm. I'm thinking there may be some unit problems here if your off by that much. What are the units you are using in your calculations, including your graph?
 
  • #5
I did some working on it today and i think you're right, I'm using Newtons, millimetres and metres in the same equation, i converted all the units properly and I've got a more sensible answer now.
 
  • #6
groom03 said:
I did some working on it today and i think you're right, I'm using Newtons, millimetres and metres in the same equation, i converted all the units properly and I've got a more sensible answer now.

Good to hear. Sometimes it always boils down to something simple like the units.
 
  • #7
Thanks for your help
 
  • #8
Anytime. :smile:
 

What is Hooke's Law?

Hooke's Law is a principle in physics that describes the relationship between the force applied to an elastic object and the resulting displacement of the object. It states that the force applied is directly proportional to the displacement of the object.

How is Hooke's Law used in real life?

Hooke's Law is used in various real-life applications, such as in the design of springs, rubber bands, and shock absorbers. It is also used in engineering and construction to determine the elasticity of materials and to design structures that can withstand certain forces.

What are the limitations of Hooke's Law?

Hooke's Law is only applicable to objects that exhibit elastic behavior, meaning they can return to their original shape after the force is removed. It also assumes that the material is being stretched or compressed within its elastic limit, meaning it will not permanently deform. Additionally, Hooke's Law is only accurate for small deformations and may not hold true for larger forces or displacements.

How is Hooke's Law related to stress and strain?

Hooke's Law can be used to understand the relationship between stress and strain in a material. Stress is the force applied to a material, while strain is the resulting deformation. Hooke's Law states that stress is directly proportional to strain, allowing us to calculate the elastic modulus of a material.

What other laws are related to Hooke's Law?

Hooke's Law is a specific case of a more general principle known as Hookian mechanics, which describes the behavior of elastic materials. It is also related to other laws such as Young's modulus, which describes the ratio of stress to strain in a material, and Poisson's ratio, which describes the relationship between lateral and axial strain in a material under stress.

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