Young's modulus

It is one of the three basic modulus.It can be called as young's moduli as well.

Young's modulus may sound a fancy name,but it is very scientific in nature and useful for a civil engineer.

It is simply defined as the ratio of force acting per uni area to the change in configuration which is length in this case.

Speaking in terms of solid physics Youngs modulus is ratio of Longitudinal stress to the longitudinal strain.

It is generally denoted by Y.

Youngs modulus can be applied to any solid which undergoes length change.

Young's moduli has two parts one is stress,other is strain to it's definition.

Now stress sounds similar to basic pressure definitiion,so it's easier to understand the concept.

So longitudinal stress is simply force acting on an object per the area on which force acts.

L.stress=F/A

F is force acting,A is area on which force acts.

Strain is a beautiful thing in physics.Strain is defined as the ratio of change in configuration to the original configuration,so strain can be negative as well as positive depending upon configuration increaseses or decreases.

L.strain =Change in length/original length

Length is taken because longitudinal strain is specifically defined for length change.

Mathematically,

L.strain=ΔL/L

ΔL is change in length and L is original length.

Strain is a dimensionless quantity,which is clearly visible from equation and it's general definition.

So,in sum young's modulus is as follows:-

Y=F/A/ΔL/L

Y=F.L/A.ΔL

Its unit are same as unit's of pressure.

In these images,these cute icecream's can be reshaped under mechanical force or force of hand and one can apply young's modulus formula to calculate it for a material,Because stick material's young modulus will differ from ice cream material's young modulus.

*Young's modulus for material's is always fixed and is a constant