# Young's Modulus in the form y = mx + cWatch

#1
I have a graph of extension against mass, and I am asked to rearrange the Young's Modulus equation into the form y = mx + c, bearing in mind that extension is on the y-axis and that mass is not a force. I'm not sure how to go about this, obviously I can arrange the Young's Modulus for extension, but I'm not sure how to get the form y = mx + c. If anyone could give a pointer that would be great.

Thanks
0
1 year ago
#2
Could you post the exact question?
0
#3
I simply have plotted a graph of extension against mass for a copper wire, and the question reads "rearrange the equation for Young's Modulus into the form y = mx + c (note that extension should be on your y axis and that mass is not a force)"

Ambiguous I know
0
1 year ago
#4
If you have a Casio F991-EX, it can do it for you.
0
#5
(Original post by Sinnoh)
If you have a Casio F991-EX, it can do it for you.
Unfortunately I don't have that
0
1 year ago
#6
(Original post by gilesm12)
Unfortunately I don't have that
100% recommend it if you're doing maths a-level.
Anyway, since stress is on the y-axis and strain is on the x-axis (hopefully) then change in stress/change in strain is equal to the Young's modulus and also the gradient. That's your "m".
Your +c would be the value of stress when strain = 0. Ideally the line should pass through the origin.
So, for the bit of the graph that's linear, stress = Young modulus * strain + c (hopefully it goes straight through the origin).
0
3 months ago
#7
This is how to do this:

Young's Modulus, E, = stress/strain
E = FL/(A delta L)
because F = T = W where W = Mg (use capital M for mass here so not to confuse little m for gradient)

So, substituting for F
E = (Mg L) / (A delta L)

Now re-arrange to put into y=mx+c
delta L = (L / AE) x Mg you would not normally need to put the +0 for +c here denoting the intercept is at the origin.

Interestingly as the gradient, m, = (L / AE) this can be re-arranged for an approximation of E because E = L / mA. This is very useful if you are to complete the Young's Modulus Required Practical in AS Physics...

Hope this helps.
0
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