# Physics question - new spec - HELP!

Watch
Announcements
#1
This is taken from last years unit 2 paper:
Why is the yield point at B and not C? Isn't the yield point the stress or force at which a large amount of plastic deformation takes place with constant or reduced load? On the graph, extension increases for a decrease in force at C, so why is B the yield point?

0
4 years ago
#2
C is the Ultimate Tensile Stress. - strongest point of wire.
0
#3
(Original post by anissabir95)
C is the Ultimate Tensile Stress. - strongest point of wire.
But doesn't C also meet the criteria to be the yield point?
And what makes B the yield point?
0
4 years ago
#4
B is the yield point, C is the UTS, you get some molecular rearrangement after yield point which lowers youngs modulus at that point but after UTS material is breaking so also some molecular reshuffle there. In general the little hump after the elastic limit is the yield point
0
#5
B is the yield point, C is the UTS, you get some molecular rearrangement after yield point which lowers youngs modulus at that point but after UTS material is breaking so also some molecular reshuffle there. In general the little hump after the elastic limit is the yield point
what from the graph made you identify B as the yield point? Just the fact that it comes after the elastic limit? Is that the only indication from the graph?
0
4 years ago
#6
(Original post by exams292)
what from the graph made you identify B as the yield point? Just the fact that it comes after the elastic limit? Is that the only indication from the graph?
That the gradient of the graph has a slight dip add to that the fact that it's not the maximum of the graph suggests it must be the yield point
1
#7
That the gradient of the graph has a slight dip add to that the fact that it's not the maximum of the graph suggests it must be the yield point
Thanks! One last thing. Can the yield point and UTS point ever coincide?
0
4 years ago
#8
(Original post by exams292)
Thanks! One last thing. Can the yield point and UTS point ever coincide?
No-as far as I know
0
#9
No-as far as I know
Ok, thanks, good luck on Wednesday
0
4 years ago
#10
(Original post by exams292)
Ok, thanks, good luck on Wednesday
Thank you
0
X

new posts
Back
to top
Latest
My Feed

### Oops, nobody has postedin the last few hours.

Why not re-start the conversation?

see more

### See more of what you like onThe Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

### Poll

Join the discussion

#### Do you think receiving Teacher Assessed Grades will impact your future?

I'm worried it will negatively impact me getting into university/college (35)
36.08%
I'm worried that Iām not academically prepared for the next stage in my educational journey (9)
9.28%
I'm worried it will impact my future career (4)
4.12%
I'm worried that my grades will be seen as ālesserā because I didnāt take exams (27)
27.84%
I donāt think that receiving these grades will impact my future (14)
14.43%
I think that receiving these grades will affect me in another way (let us know in the discussion!) (8)
8.25%