# Relationship of Young's modulus and impulse force

• Howard_SSS
In summary, the conversation discusses the possibility of obtaining a relationship between Young's modulus of a spring and impulse force with given information. The suggested equation is J/t = (EA/L)*(x), but it is noted that the cross-sectional area A is an essential value and cannot be omitted. It is mentioned that for a regular coiled spring, Young's modulus is more suitable and already incorporates the details of the spring structure, and can be expressed as Y=kL0. f

## Homework Statement

Is that possible to obtain the a relationship between Young's modulus of a spring and impulse force with below information ? I personally think that we cannot if without the given cross-sectional area A and the given spring constant k.

The particle is connect to a elastic spring, then an external impulse force horizontally was added to it.
(Smooth plate)

The given values are :

Particle mass ''m'', spring of modulus of elasticity ''E'', spring's natural length ''L'', received impulse ''J'', impulse reaction time ''t'', displacement ''x''

2. Homework Equations ## The Attempt at a Solution

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F = kx => J/t = (EA/L) * (x)

Looks like the area is an essential value or we cannot express the equation for them. E there is not Young's modulus of a spring. Young's modulus, often written as Y, is related to the spring constant k by Y=kL0.
F = kx => J/t
Not in this case. J=∫F.dt. You can only simplify that to J=Ft if F is constant.

E there is not Young's modulus of a spring. Young's modulus, often written as Y, is related to the spring constant k by Y=kL0.

Not in this case. J=∫F.dt. You can only simplify that to J=Ft if F is constant.
Thanks for this reminding.

For Y=k*L0, may I know why you can remove the A (cross sectional area) ?

Thanks for this reminding.

For Y=k*L0, may I know why you can remove the A (cross sectional area) ?
EA, where E is the elastic modulus (not Young's modulus) is for a stretched wire. A regular coiled spring works by torsion, not by stretching of the material. Young's modulus is more suitable, and already incorporates the details of the spring structure. It is defined as the force per fractional change in spring length, so Y=kL0.

• Howard_SSS