Answer:
Explanation:
Original diameter = 5mm
d= 0.005m. r=0.0025m
True stress (σ) = 290MPa
Coefficient of annealing copper (n)=0.5
True stress is given as force/area
σ=F/A
Ao=πr^2
Ao=1.963×10^-5m2
F=σ ×A
F=290×10^6 ×π×(0.0025)^2
F= 5694.13N
Given that
σ=Kε^n
290=Kε^0.5
n=ε=0.5 at necking
Therefore
290=K×0.5^0.5
K=410.12MPa
ε=In(Ao/A)
0.5=In(π×0.0025^2/A)
exp(0.5)=1.96×10^-5/A
A=1.96×10^-5/exp(0.5)
A= 1.2×10^-5m2
This is the new area
Then the Ultimate Tensile Stress
σ=F/A
σ=5694.13/1.2×10^-5
σ=4.75×10^8Pa
σ=475MPa
Therefore,
The ultimate tensile stress is 475MPa.
The maximum tension is
Fo/Ao=F/A
F=(Fo/Ao) ×A
F=(5694.13/1963×10^-5)×1.2×10^-5
F= 3479.99
F=3480N.
The probability of a woman wearing green walking into a restaurant 48%
Answer:
(a) B = 2.85 ×
Tesla
(b) I = I = 0.285 A
Explanation:
a. The strength of magnetic field, B, in a solenoid is determined by;
r = 
⇒ B = 
Where: r is the radius, m is the mass of the electron, v is its velocity, q is the charge on the electron and B is the magnetic field
B = 
= 
B = 2.85 ×
Tesla
b. Given that; N/L = 25 turns per centimetre, then the current, I, can be determined by;
B = μ I N/L
⇒ I = B ÷ μN/L
where B is the magnetic field, μ is the permeability of free space = 4.0 ×
Tm/A, N/L is the number of turns per length.
I = B ÷ μN/L
= 
I = 0.285 A
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