The question is incomplete. The complete question is :
The solid rod shown is fixed to a wall, and a torque T = 85N?m is applied to the end of the rod. The diameter of the rod is 46mm .
When the rod is circular, radial lines remain straight and sections perpendicular to the axis do not warp. In this case, the strains vary linearly along radial lines. Within the proportional limit, the stress also varies linearly along radial lines. If point A is located 12 mm from the center of the rod, what is the magnitude of the shear stress at that point?
Solution :
Given data :
Diameter of the rod : 46 mm
Torque, T = 85 Nm
The polar moment of inertia of the shaft is given by :


J = 207.6 
So the shear stress at point A is :



Therefore, the magnitude of the shear stress at point A is 4913.29 MPa.
Answer:
Explanation:
Since there are six points, the minimum distance from all points would be the centroid of polygon formed by A,B,C,D,E,F
To find the coordinates of centroid of a polygon we use the following formula. Let A be area of the polygon.
where i=1 to N-1 and N=6
A area of the polygon can be found by the following formula
where i=1 to N-1
![A=\frac{1}{2}[ (x_{1} y_{2} -x_{2} y_{1})+ (x_{2} y_{3} -x_{3} y_{2})+(x_{3} y_{4} -x_{4} y_{3})+(x_{4} y_{5} -x_{5} y_{4})+(x_{5} y_{6} -x_{6} y_{5})]](https://tex.z-dn.net/?f=A%3D%5Cfrac%7B1%7D%7B2%7D%5B%20%28x_%7B1%7D%20%20y_%7B2%7D%20-x_%7B2%7D%20%20y_%7B1%7D%29%2B%20%28x_%7B2%7D%20%20y_%7B3%7D%20-x_%7B3%7D%20%20y_%7B2%7D%29%2B%28x_%7B3%7D%20%20y_%7B4%7D%20-x_%7B4%7D%20%20y_%7B3%7D%29%2B%28x_%7B4%7D%20%20y_%7B5%7D%20-x_%7B5%7D%20%20y_%7B4%7D%29%2B%28x_%7B5%7D%20%20y_%7B6%7D%20-x_%7B6%7D%20%20y_%7B5%7D%29%5D)
A=0.5[(20×25 -25×15) +(25×32 -13×25)+(13×21 -4×32)+(4×8 -18×21)+(18×14 -25×8)
A=225.5 miles²
Now putting the value of area in Cx and Cy
![C_{x} =\frac{1}{6A}[ [(x_{1}+x_{2})(x_{1} y_{2} -x_{2} y_{1})]+ [(x_{2}+x_{3})(x_{2} y_{3} -x_{3} y_{2})]+[(x_{3}+x_{4})(x_{3} y_{4} -x_{4} y_{3})]+[(x_{4}+x_{5})(x_{4} y_{5} -x_{5} y_{4})]+[(x_{5}+x_{6})(x_{5} y_{6} -x_{6} y_{5})]]](https://tex.z-dn.net/?f=C_%7Bx%7D%20%3D%5Cfrac%7B1%7D%7B6A%7D%5B%20%5B%28x_%7B1%7D%2Bx_%7B2%7D%29%28x_%7B1%7D%20%20y_%7B2%7D%20-x_%7B2%7D%20%20y_%7B1%7D%29%5D%2B%20%5B%28x_%7B2%7D%2Bx_%7B3%7D%29%28x_%7B2%7D%20%20y_%7B3%7D%20-x_%7B3%7D%20%20y_%7B2%7D%29%5D%2B%5B%28x_%7B3%7D%2Bx_%7B4%7D%29%28x_%7B3%7D%20%20y_%7B4%7D%20-x_%7B4%7D%20%20y_%7B3%7D%29%5D%2B%5B%28x_%7B4%7D%2Bx_%7B5%7D%29%28x_%7B4%7D%20%20y_%7B5%7D%20-x_%7B5%7D%20%20y_%7B4%7D%29%5D%2B%5B%28x_%7B5%7D%2Bx_%7B6%7D%29%28x_%7B5%7D%20%20y_%7B6%7D%20-x_%7B6%7D%20%20y_%7B5%7D%29%5D%5D)
putting the values of x's and y's you will get

For Cy
![C_{y} =\frac{1}{6A}[ [(y_{1}+y_{2})(x_{1} y_{2} -x_{2} y_{1})]+ [(y_{2}+y_{3})(x_{2} y_{3} -x_{3} y_{2})]+[(y_{3}+y_{4})(x_{3} y_{4} -x_{4} y_{3})]+[(y_{4}+y_{5})(x_{4} y_{5} -x_{5} y_{4})]+[(y_{5}+y_{6})(x_{5} y_{6} -x_{6} y_{5})]]](https://tex.z-dn.net/?f=C_%7By%7D%20%3D%5Cfrac%7B1%7D%7B6A%7D%5B%20%5B%28y_%7B1%7D%2By_%7B2%7D%29%28x_%7B1%7D%20%20y_%7B2%7D%20-x_%7B2%7D%20%20y_%7B1%7D%29%5D%2B%20%5B%28y_%7B2%7D%2By_%7B3%7D%29%28x_%7B2%7D%20%20y_%7B3%7D%20-x_%7B3%7D%20%20y_%7B2%7D%29%5D%2B%5B%28y_%7B3%7D%2By_%7B4%7D%29%28x_%7B3%7D%20%20y_%7B4%7D%20-x_%7B4%7D%20%20y_%7B3%7D%29%5D%2B%5B%28y_%7B4%7D%2By_%7B5%7D%29%28x_%7B4%7D%20%20y_%7B5%7D%20-x_%7B5%7D%20%20y_%7B4%7D%29%5D%2B%5B%28y_%7B5%7D%2By_%7B6%7D%29%28x_%7B5%7D%20%20y_%7B6%7D%20-x_%7B6%7D%20%20y_%7B5%7D%29%5D%5D)
putting the values of x's and y's you will get

So coordinates for the fire station should be (15.36,22.55)
Complete question:
A structural component in the form of a wide plate is to be fabricated from a steel alloy that has a plane strain fracture toughness of 98.9 MPa root m (90 ksi root in.) and a yield strength of 860 MPa (125,000 psi). The flaw size resolution limit of the flaw detection apparatus is 3.0 mm (0.12 in.). If the design stress is one-half of the yield strength and the value of Y is 1.0, determine whether or not a critical flaw for this plate is subject to detection.
Answer:
Since the flaw 17mm is greater than 3 mm the critical flaw for this plate is subject to detection
so that critical flow is subject to detection
Explanation:
We are given:
Plane strain fracture toughness K 
Yield strength Y = 860 MPa
Flaw detection apparatus = 3.0mm (12in)
y = 1.0
Let's use the expression:

We already know
K= design
a = length of surface creak
Since we are to find the length of surface creak, we will make "a" subject of the formula in the expression above.
Therefore
![a= \frac{1}{pi} * [\frac{k}{y*a}]^2](https://tex.z-dn.net/?f=%20a%3D%20%5Cfrac%7B1%7D%7Bpi%7D%20%2A%20%5B%5Cfrac%7Bk%7D%7By%2Aa%7D%5D%5E2%20)
Substituting figures in the expression above, we have:
![= \frac{1}{pi} * [\frac{98.9 MPa \sqrt{m}} {10 * \frac{860MPa}{2}}]^2](https://tex.z-dn.net/?f=%20%3D%20%5Cfrac%7B1%7D%7Bpi%7D%20%2A%20%5B%5Cfrac%7B98.9%20MPa%20%5Csqrt%7Bm%7D%7D%20%7B10%20%2A%20%5Cfrac%7B860MPa%7D%7B2%7D%7D%5D%5E2)
= 0.0168 m
= 17mm
Therefore, since the flaw 17mm > 3 mm the critical flow is subject to detection