Answer:
a) 53 MPa, 14.87 degree
b) 60.5 MPa
Average shear = -7.5 MPa
Explanation:
Given
A = 45
B = -60
C = 30
a) stress P1 = (A+B)/2 + Sqrt ({(A-B)/2}^2 + C)
Substituting the given values, we get -
P1 = (45-60)/2 + Sqrt ({(45-(-60))/2}^2 + 30)
P1 = 53 MPa
Likewise P2 = (A+B)/2 - Sqrt ({(A-B)/2}^2 + C)
Substituting the given values, we get -
P1 = (45-60)/2 - Sqrt ({(45-(-60))/2}^2 + 30)
P1 = -68 MPa
Tan 2a = C/{(A-B)/2}
Tan 2a = 30/(45+60)/2
a = 14.87 degree
Principal stress
p1 = (45+60)/2 + (45-60)/2 cos 2a + 30 sin2a = 53 MPa
b) Shear stress in plane
Sqrt ({(45-(-60))/2}^2 + 30) = 60.5 MPa
Average = (45-(-60))/2 = -7.5 MPa
Answer:

Explanation:
From the question we are told that:
Temperature of silicon 
Electron concentration 
Electron diffusion coefficient is
Electron mobility is 
Electron current density 
Generally the equation for the semiconductor is mathematically given by

Therefore



Answer:
28 , 24-inch screwdrivers
Explanation:
The total number of screwdrivers that can be purchased is = 70
4 - inch length screwdrivers = 10
6- inch length screwdrivers = 12
8- inch length screwdrivers = 20
Total = 20 +12 +10 = 42
Remaining = 70-42 = 28
So, heavy 24-inch screwdrivers = 28