Answer:
2800 [MPa]
Explanation:
In fracture mechanics, whenever a crack has the shape of a hole, and the stress is perpendicular to the orientation of such, we can use a simple formula to calculate the maximum stress at the crack tip

Where
is the magnitude of he maximum stress at the tip of the crack,
is the magnitude of the tensile stress,
is
the length of the internal crack, and
is the radius of curvature of the crack.
We have:
![r_{c}=1.9*10^{-4} [mm]](https://tex.z-dn.net/?f=r_%7Bc%7D%3D1.9%2A10%5E%7B-4%7D%20%5Bmm%5D)
![l_{c}=3.8*10^{-2} [mm]](https://tex.z-dn.net/?f=l_%7Bc%7D%3D3.8%2A10%5E%7B-2%7D%20%5Bmm%5D)
![\sigma_{c}=140 [MPa]](https://tex.z-dn.net/?f=%5Csigma_%7Bc%7D%3D140%20%5BMPa%5D)
We replace:
![\sigma_{m} = 2*(140 [MPa])*(\frac{\frac{3.8*10^{-2} [mm]}{2}}{1.9*10^{-4} [mm]})^{0.5}](https://tex.z-dn.net/?f=%5Csigma_%7Bm%7D%20%3D%202%2A%28140%20%5BMPa%5D%29%2A%28%5Cfrac%7B%5Cfrac%7B3.8%2A10%5E%7B-2%7D%20%5Bmm%5D%7D%7B2%7D%7D%7B1.9%2A10%5E%7B-4%7D%20%5Bmm%5D%7D%29%5E%7B0.5%7D)
We get:
![\sigma_{m} = 2*(140 [MPa])*(\frac{\frac{3.8*10^{-2} [mm]}{2}}{1.9*10^{-4} [mm]})^{0.5}=2800 [MPa]](https://tex.z-dn.net/?f=%5Csigma_%7Bm%7D%20%3D%202%2A%28140%20%5BMPa%5D%29%2A%28%5Cfrac%7B%5Cfrac%7B3.8%2A10%5E%7B-2%7D%20%5Bmm%5D%7D%7B2%7D%7D%7B1.9%2A10%5E%7B-4%7D%20%5Bmm%5D%7D%29%5E%7B0.5%7D%3D2800%20%5BMPa%5D)
Answer:
im so sorry I rlly need these points
Explanation:
Answer:
Option A
Explanation:
Please find the attachment