Register to reply

Rubber bands and Hooke's Law

by Manchot
Tags: bands, hooke, rubber
Share this thread:
Oct25-04, 09:51 PM
P: 728
I have found a website which claims that rubber bands obey a force law
While this is similar to Hooke's Law in the sense that it *almost* approaches it for large values of x, it is also quite different. Can anyone confirm or deny the formula's reliability? Thanks.
Phys.Org News Partner Physics news on
Researchers demonstrate ultra low-field nuclear magnetic resonance using Earth's magnetic field
Bubbling down: Discovery suggests surprising uses for common bubbles
New non-metallic metamaterial enables team to 'compress' and contain light
Oct26-04, 11:12 AM
Sci Advisor
PF Gold
Gokul43201's Avatar
P: 11,155
Are you sure [itex]x = L/L_0~~and~not~~\delta L/L_0~[/itex] ?
Oct26-04, 11:26 AM
P: 728
No, I'm not sure.

Oct26-04, 11:34 AM
HW Helper
Pyrrhus's Avatar
P: 2,277
Rubber bands and Hooke's Law

Well if you're familiar with elasticity you can formulate Hooke's Law in its terms,

Stress = Modulus of Elasticity x Relative Deformation

For a longitudinal deformation, the modulus is called Young's modulus

[tex] \sigma = Y \delta L [/tex]

Since Stress = Force/Area

[tex] \frac{F}{A} = Y \delta L [/tex]

[tex] F = YA \delta L [/tex]

You know

[tex] \delta L = \frac{\Delta L}{L_{o}} [/tex]

[tex] F = YA \frac{\Delta L}{L_{o}} [/tex]


[tex] F = \frac{YA}{L_{o}} \Delta L [/tex]

we have

[tex] F = \frac{YA}{L_{o}} \Delta L [/tex]

Hooke's Law

[tex] F = k \Delta x [/tex]

where k in our equation is (x = L)

[tex] k = \frac{YA}{L_{o}} [/tex]

The people from that page probably tried something similar, can you give us the website?
Oct26-04, 12:01 PM
Sci Advisor
HW Helper
PF Gold
P: 12,016
The given formula, in order to be meaningful must have [tex]x=\frac{L}{L_{0}}[/tex]

Rewritten slightly, it simply says:

Hence, it predicts a hardening for compression of the rubber.
I don't know if it actually is good, though..
Oct26-04, 01:54 PM
P: 728
This is the website that I got the information from: . It's about two-thirds down the page.
Oct26-04, 02:50 PM
Sci Advisor
PF Gold
PerennialII's Avatar
P: 1,102
The given formula, in order to be meaningful must have x=L/L0 ...
Which is what they give under the link. So it looks like a simple uniaxial time-independent hardening mod of sorts ... so is it just a simple made up correction or does it have any theoretical merit ?

Register to reply

Related Discussions
Innovative applications of Rubber Bands (Stanford U.) General Discussion 2
Rubber Bands and Energy Dissipation General Physics 7
Projectile motion via a spring (well, actually, rubber bands...) Introductory Physics Homework 12
Need help on rubber band and Hooke's Law Introductory Physics Homework 6
Rubber Bands and Paper Clip Engineering Systems & Design 1