Remy noticed that after oiling his skateboard wheels, it was easier to reach the speeds he needed to perform tricks. How did the
1 answer:
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Answer:
a) The ductility = -30.12%
the negative sign means reduction
Therefore, there is 30.12% reduction
b) the true stress at fracture is 658.26 Mpa
Explanation:
Given that;
Original diameter = 12.8 mm
Final diameter = 10.7
Engineering stress = 460 Mpa
a) determine The ductility in terms of percent reduction in area;
Ai = π/4( )² ; Ag = π/4(
)²
% = π/4 [ ( ( )² - (
)²) / ( π/4 (
)²) ]
= ( ( )² - (
)²) / (
)² × 100
we substitute
= [( (10.7)² - (12.8)²) / (12.8)² ] × 100
= [(114.49 - 163.84) / 163.84 ] × 100
= - 0.3012 × 100
= -30.12%
the negative sign means reduction
Therefore, there is 30.12% reduction
b) The true stress at fracture;
True stress =
( 1 +
)
is engineering strain
= dL / Lo
= (do² - df²) / df² = (12.8² - 10.7²) / 10.7² = (163.84 - 114.49) / 114.49
= 49.35 / 114.49
= 0.431
so we substitute the value of into our initial equation;
True stress = 460 ( 1 + 0.431)
True stress = 460 (1.431)
True stress = 658.26 Mpa
Therefore, the true stress at fracture is 658.26 Mpa
Answer:
Option A
Explanation:
Answer:
The answer is given in the explanation.
Explanation:
The circuit is as indicated in the attached figure.
From the analytical description the zener voltage is given as
Here
Vzo is the voltage at which the slope of 1/rz intersects the voltage axis it is equal to knee voltage.
The equivalent model is shown in the attached figure.
From the above equation, Vzo is calculated as
Here Vz is given as 7.5 V
Iz is given as 10 mA
rz is given as 30 Ω
Thus the Vzo is given as
The value of I_L is given as 5 mA
Now the expression of current is as
Now the resistance is calculated as
So the value of resistance is 186.66 Ω.
Considering the supply voltage is increased by 10%
V is 10-10%*10=10+1=11 so the
Considering the supply voltage is decreased by 10%
V is 10-10%*10=10-1=9 so the
Now if the supply voltage is 10% high and the value of Load is removed i.e I=Iz only which is 10mA
so
Now the largest load current thus that the supply voltage is 10% low and the current of zener is knee current thus
The load voltage is 7.485 V
