# What is Young modulus: Definition and 34 Discussions

Young's modulus

E

{\displaystyle E}
, the Young modulus, or the modulus of elasticity in tension, is a mechanical property that measures the tensile stiffness of a solid material. It quantifies the relationship between tensile stress

σ

{\displaystyle \sigma }
(force per unit area) and axial strain

ε

{\displaystyle \varepsilon }
(proportional deformation) in the linear elastic region of a material and is determined using the formula:

E
=

σ
ε

{\displaystyle E={\frac {\sigma }{\varepsilon }}}
Young's moduli are typically so large that they are expressed not in pascals but in gigapascals (GPa).
Although Young's modulus is named after the 19th-century British scientist Thomas Young, the concept was developed in 1727 by Leonhard Euler. The first experiments that used the concept of Young's modulus in its current form were performed by the Italian scientist Giordano Riccati in 1782, pre-dating Young's work by 25 years. The term modulus is derived from the Latin root term modus which means measure.

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1. ### Which material has the greatest Young's Modulus?

My answer is (B) since it has the highest slope for the straight line part of the graph but the answer key is (A). Is it because the slope of graph B will decrease until the value less than slope A? So we don't only consider the straight line part but the whole graph? Thanks
2. ### Determine equivalent Young's Modulus

We need to find a single wire supporting the load. But, when I think about it there can so many different types of materials we could use for the single wire and each of these single wires would have a different Young's Modulus. So, I don't get what equivalent means here? Anyways, I get the...
3. ### B Suggestions for Internal Assessment Project on Young's Modulus

Hi. I am in the IB and am looking at doing a physics IA (internal assessment) on Young's modulus on an elastic material. I was thinking of doing it on the the stretchy snakes like the candy. What would I need to cover in this?
4. ### B Why is Young's modulus constant below the limit of proportionality?

Hi all, I'm a little confused about something. Force-extension graphs and stress-strain graphs are always both straight lines up until the limit of proportionality, implying both the spring constant and the Young modulus are constant up until then. For a force-extension graph, Hooke's Law...
5. ### Young's modulus of a steel post, finding change in length

Homework Statement Superman pulls on a steel post to trap a supervillian. The post has a cross-sectional area of 30cm^2 and a length of 2m. If Superman applies a force of 6X10^6N by how much is the length of the post increased? A) 2mm B) 7mm C) 1.2cm D) 1.7cm E) 2cm Homework Equations...
6. ### Stretching of a wire due to it's weight

Homework Statement 1) calculate the longest length of steel wire that can hang vertically without breaking .breaking stress for steel=7.982*10^8N/m^2 and density of steel(d)=8.1*10^3kg/m^3.2)A bar of mass m and length l is hanging from a point A as shown in the figure.Find the increase...
7. ### Find out the Young's modulus of a carbon fiber lamina composite

Hello everyone, nice to be here. I am going to calculate the young modulus of 3 layers of carbon fiber laminar composite For example: 1st: 12K plain wave carbon fiber in 0 degree 2nd:3K till wave carbon fiber in 45deg 3rd:12K plain wave carbon fiber in 0 degree How can I approach to calculate...
8. ### MHB Find force with Young's modulus

Q: Calculate the force (in N) a piano tuner applies to stretch a steel piano wire 8.50 mm, if the wire is originally 0.850 mm in diameter and 1.35 m long. (Young's modulus for steel is 20.0 ✕ 1010 Pa.) Work F=Y*A*change in L/L_0 I have no idea what is L_0 and L_f? Please help me.
9. ### By how much is each post compressed?

Homework Statement A large 30000 L aquarium is supported by four wood posts at the corners. Each post has a square 6.00 cm x 6.00 cm cross section and is 90.0 cm tall. Take Y=10^10 for wood Homework Equations ΔL = FL/AY F = ma ρ = m/V The Attempt at a Solution So the total area is 0.06 * 0.06...
10. ### Determining Young's Modulus of Aluminium from Tensile Test

My Aim is to determine the youngs modulus of aluminium from the data we get from tensile strength test. The attached excel sheet contains all the data i am using such as elongation,load value(which is in kN i have converted to N for calculating Stress) For stress, I am using the formula...
11. ### Relation between Young's modulus and the coefficient of thermal expansion

Is it true for all material that if young's modulus is high then melting point will be high and coeff of thermal expansion will be lower? Any example that doesn't follow the above statement. Many Thanks
12. ### Differences in Young Modulus -> Tensile/Compressive tests

Hello everybody. I've measured the Young Modulus of PDMS samples both in compression and in tension. From compressive tests I get a Modulus twice as big as the one I get from tensile tests. Is it normal to get two different values for Young Modulus using tensile or compressive tests? Do you...
13. ### What is the relationship between stiffness and Young Modulus?

What is the difference between stiffness and Young Modulus and how can you calculate the stiffness?
14. ### Why is length independent of young modulus ?

If young modulus = stress/strain Wouldn't a different original length affect the value of young modulus ?
15. ### Different young modulus of rod - Need a proper explanation?

Homework Statement A rod is made up as shown [pic attached] Both have same cross-sectional area. Ep and En are Young modulus. The rod breaks when total extension = 3.0mm Greatest tensile stress that can be applied before rod breaks? Homework Equations Young modulus = stress / strain The...
16. ### Young modulus (deriving formula)

Quoted from my book: "The graph of ΔL against F has gradient L/EA, so the Young modulus E is equal to L(A x gradient)." E is (stress/strain). I don't understand that sentence. If I substitute the gradient into E= L(A x gradient), then E= L(A)(L/EA) E= L(L/E) E= L^2 /E E square = L square...
17. ### What are the Reasons for the Experiment Set-Up in Measuring Young's Modulus?

Question 1: --> Why both the wires are suspended from the same rigid support in this experiment? Question 2: -->Why both the wires are taken of the same material?
18. ### Strain and stress related to young modulus

Homework Statement A three-legged stool has one leg of aluminium (E = 7 x 1010 Pa), one copper (E = 11 x 1010 Pa) and one of steel (E = 20 x 1010) Pa. The legs have the same dimensions. If the load on the stool is at the exact center, a. Which leg is under the greatest stress? Explain why b...
19. ### Is Elastance equal young modulus?

Hi, dear all, Recently face some controversial issue with my supervisor and i cannot convince my self too. is it time varying elastance equal to time varying young modulus? Young modulus unit is Pa, however, elastance value is mmHg/ml, is both of them are equal? Young's modulus, also...
20. ### What Is the Correct Stress Calculation for a Wire Under Tension?

Homework Statement Calculate the stress in a wire of diameter 0.35mm when the tension in the wire is 50N. Homework Equations Stress=F/A The Attempt at a Solution 0.25/2=0.125 0.125/100=1.25x10"-3 Pi x 0.00125"2 = 1.542x10"-5 50/1.542x10"-5 = 3242542.153 Pa Are my...
21. ### Young modulus diameter question

I have started a home study course in mechanical engineering, I now realize that I should have started with a math’s course but any way I have a question that I could do with some help with. A designer wishes to calculate the thickness (diameter) of a steel cable for suspending a passenger lift...
22. ### Cross sectional area - Young Modulus

out of interest does cross sectional area change when a force is applied (lets say I had a wire and I applied a force to it, the wire would stretch ) does its cross sectional area change
23. ### Does Higher Young Modulus Indicate Increased Rigidity in Solids?

Hi, does higher young modulus means higher rigidity of a solide? Regards,
24. ### What is the Force Due to Extension for a Particle on an Elastic String?

Homework Statement A particle of mass m is attached to one end of a light elastic string of natural length a and modulus mg, the other end of the sting is attached to a fixed point O on smooth horizontal surface. The particle is released from rest at horizontal distance a+L from O...
25. ### Young Modulus calculation

Hi I have a problem with the following question: A steel violin string has a cross-sectional area of 0.2*10^-6 m^2 and is under tension 83N. If its length under tension is 35cm, find its original length. I can not seem to solve the question without needing the value of young modulus...
26. ### What is Young Modulus and Why Does it Matter?

in young modulus of a metal bar , we have a horizontal bar on one side we attach some weight so there is some change in angle but no change in length then why it is called young modulus?
27. ### Measurement of Young modulus of Copper

Homework Statement my data as below diameter of copper wire/m 0.025 (mean) Unstretched part = 0.285m mass(m)/KG extension(e)/m 0.1 0 0.2 0 0.3 0 0.4 0.001 0.5 0.001 0.6 0.001 0.7 0.003 0.8...
28. ### Stress and strain. young modulus

in the following question, how do i find the changle in AB, the change in AD and the change in AC? http://lh4.ggpht.com/_H4Iz7SmBrbk/Sv_hYT83rYI/AAAAAAAAB8s/7l5YRXMxVfQ/s912/Capture.JP what i have done is used the following \sigmaxx=E*\epsilonxx \deltaAB=\epsilonAB*AB since AB is on the x...
29. ### Material coursework- young modulus of copper

Homework Statement find the young modulus of copper through calculating the stress and strain, plotting on a graph and finding the gradient of the linear part of the graph Homework Equations ym=stress/strain stress=force/ area strain= extension/length The Attempt at a Solution...
30. ### The difference of bulk and young modulus

Hi everyone, I want to know what the difference between bulk modulus and young modulus is? In some papers, it seems that they have compared the value of these two as if they are the same. Could anyone help me with this regard? Regards, Sara
31. ### How Much Does an Empty Lift Move When Entered by 8 Passengers?

Homework Statement The cables of length 70m supporting a lift consist of two steel ropes each of 100 strangs giving a total cross sectional area of 1.0 x 10^-4 m^2. Consider a full lift to carry 8 passengers of average mass 75kg. Calculate by how much an empty lift moves down when it is...
32. ### What is the Young Modulus of Nylon Rope?

Homework Statement The problem is that I do not have a way of making a nylon rope young modulus stress/strain graph I did not know is anyone would be able to help me obtain the information on the stress and strain or if your feeling really nice make me up a graph! young modulus = stress...
33. ### Salters Hornes CWK Young Modulus of a scooby

My cwk is investigating the youngs modulus of a scooby. A scooby is a hollow plastic string like thing. My experiment used the pulley clamped to the bench method and attaching weights. I have my results and have worked out the change in area for each load and have a graph of stesslog10 vs...