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ross1
Feb 15, 2012, 12:37 AM
I'm new to this game and the question probably isn't that hard but I can't make sense of it!
here's the question & it's related to engineering
"When in operation,the shafts are found to have stretched over 19mm diameter by 0.24mm. Caculate the actual stress in the shafts if E is 200GN/m2".
Given E = stress/strain: strain = change in length/original: strain = 0.24/381 = 6.3 x 10 to the power minus 4.
Transpose the formula first and show all workings
If you can explain this to me I'd appreciate it. Thanks Ross

ebaines
Feb 16, 2012, 01:24 PM
Stress and strain are related by Young's modulus, E:

E = =stress/strain.

So to calculate stress given the strain and Young's modulus simply reaarrange to get:

E x strain = stress.

Here you know that E = 200 x 10^9 N/m^2, and strain = 6.3 x 10^(-4), so

stress = 200 x 10^9N/m^2 x 6.3 x 10(-4) = 1.26 x 10^8 N/m^2