# Homework Help: Ultimate tensile stress of rubber?

1. Nov 6, 2008

### GaussModulus

1. The problem statement, all variables and given/known data

How would you define the ultimate tensile stress of rubber?

2. Relevant equations

If I had a force/extension graph of rubber, what point in the graph would show me the value of the ultimate tensile stress??

3. The attempt at a solution
Is it the same thing as ultimate tensile strength??

Help much appreciated
Thanks
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Nov 6, 2008

### mgb_phys

Ultimate tensile stress is the stress (force/area = pressure) that it breaks at.
The complication for plastic materials is that the cross section area changes so at constant tension the stress is changing.
Ultimate tensile strength is normally defined for a specific component with a given area so it has units of force rather than pressure.