Answer:
7.7 kN
Explanation:
The capacity of a material having a crack to withstand fracture is referred to as fracture toughness.
It can be expressed by using the formula:
![K = \sigma Y \sqrt{\pi a}](https://tex.z-dn.net/?f=K%20%3D%20%5Csigma%20Y%20%5Csqrt%7B%5Cpi%20a%7D)
where;
fracture toughness K = 137 MPa![m^{1/2}](https://tex.z-dn.net/?f=m%5E%7B1%2F2%7D)
geometry factor Y = 1
applied stress
= ???
crack length a = 2mm = 0.002
∴
![137 =\sigma \times 1 \sqrt{ \pi \times 0.002 }](https://tex.z-dn.net/?f=137%20%3D%5Csigma%20%5Ctimes%201%20%20%5Csqrt%7B%20%5Cpi%20%5Ctimes%200.002%20%7D)
![137 =\sigma \times 0.07926](https://tex.z-dn.net/?f=137%20%3D%5Csigma%20%5Ctimes%200.07926)
![\dfrac{137}{0.07926} =\sigma](https://tex.z-dn.net/?f=%5Cdfrac%7B137%7D%7B0.07926%7D%20%3D%5Csigma)
![\sigma = 1728.489 MPa](https://tex.z-dn.net/?f=%5Csigma%20%3D%201728.489%20MPa)
Now, the tensile impact obtained is:
![\sigma = \dfrac{P}{A}](https://tex.z-dn.net/?f=%5Csigma%20%3D%20%5Cdfrac%7BP%7D%7BA%7D)
P = A × σ
P = 1728.289 × 4.5
P = 7777.30 N
P = 7.7 kN
mark me the brainiest here
average speed (in km/h) of a car stuck in traffic that drives 12 kilometers in 2 hours.
Answer: the standard deviation STD of machine B is s (Lb) = 0.4557
Explanation:
from the given data, machine A and machine B produce half of the rods
Lt = 0.5La + 0.5Lb
so
s² (Lt) = 0.5²s²(La) + 0.5²s²(Lb) + 0.5²(2)Cov (La, Lb)
but Cov (La, Lb) = Corr(La, Lb) s(La) s(Lb) = 0.4s (La) s(Lb)
so we substitute
s²(Lt) = 0.25s² (La) + 0.25s² (Lb) + 0.4s (La) s(Lb)
0.4² = 0.25 (0.5²) + 0.25s² (Lb) + (0.5)0.4(0.5) s(Lb)
0.64 = 0.25 + s²(Lb) + 0.4s(Lb)
s²(Lb) + 0.4s(Lb) - 0.39 = 0
s(Lb) = { -0.4 ± √(0.16 + (4*0.39)) } / 2
s (Lb) = 0.4557
therefore the standard deviation STD of machine B is s (Lb) = 0.4557
This statement is b which is true: hope this helped
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