You are Here: Home >< Physics

# Stress-strain watch

1. I just really don't understand the concepts of stiffness, toughness, elasticity and brittle in stress/strain graphs. How do I know when something is more/less brittle than another, and is stiffness just to do with the steepness of the line. Also, if the gradient is curved, is it more elastic than a straight line?
Thanks!
2. stiffness is the ability of an object to resist extension when a force is applied to it. the higher the stiffness, the lower the extension when the same magnitude of force is applied to another material of a lower stiffness. stiffness is also the spring constant in hookes law.

Think of a stress(y)-strain(X) graph. if the gradient is high, the object experiences a lot of force but doesn't extend much so it has a high stiffness.
3. (Original post by BTAnonymous)
stiffness is the ability of an object to resist extension when a force is applied to it. the higher the stiffness, the lower the extension when the same magnitude of force is applied to another material of a lower stiffness. stiffness is also the spring constant in hookes law.

Think of a stress(y)-strain(X) graph. if the gradient is high, the object experiences a lot of force but doesn't extend much so it has a high stiffness.
Thank you! Can you please explain how I know if a material is ductile/ plastic?
4. physics exams are over tho
5. (Original post by aceplayyt)
physics exams are over tho
aqa alevel hasn't even started

people sit different exams you know
6. (Original post by BTAnonymous)
aqa alevel hasn't even started

people sit different exams you know
oh rip thought all the boards were on the same date
7. (Original post by aceplayyt)
oh rip thought all the boards were on the same date
Yup, i have all 9 exams this june.
8. (Original post by aceplayyt)
physics exams are over tho
Haha no this is an internal for my first year, I'm takingg the full A level( it's bloody awful tho, at 100 minutes for 50 multiple choice and 1 long answer...
9. (Original post by BTAnonymous)
Yup, i have all 9 exams this june.
damn good luck Im lucky mine were split 5 in may and 5 in june
10. Ductile - Material will undergo a lot of strain for a very small amount of stress
11. (Original post by BTAnonymous)
Yup, i have all 9 exams this june.
9 exams!! Good luck!
12. (Original post by Thomas_Grimes_17)
Ductile - Material will undergo a lot of strain for a very small amount of stress
Thank you! Does the material have to have a bendy region? Like is it considered ductile/ plastic after the limit of proportionality is passed?
13. Yes! If something is ductile, it undergoes plastic deformation when it is drawn out.

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: May 20, 2018
Today on TSR

### Uni league tables

Do they actually matter?

### University open days

• Staffordshire University
Everything except: Midwifery, Operating Department Practice, Paramedic Undergraduate
Sun, 21 Oct '18
• University of Exeter
Wed, 24 Oct '18