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3 years ago

Phân tích phương pháp gia công plasma

Engineering

1 answer:

Irina-Kira [14]3 years ago

7 0

Answer:

can you plz write in English language so we can give you answer

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The resistance of a copper wire 200 m long is 21 Q. If its thickness (diameter) is 0.44 mm, its specific resistance is around___

fenix001 [56]

Answer:

Its specific resistance will be around 0.015

7 0

3 years ago

A drainage ditch alongside a highway with a 3% grade has a rectangular cross-section of depth 4 ft and width 8 ft, and is fully

bekas [8.4K]

To solve the problem it is necessary to use the concepts related to frictional dissipation per unit mass, energy balance equation and Volumetric flow rate.

The frictional dissipation per unit mass is defined as

$F = \frac{150u_0\mu L(1-\epsilon)^2}{\rho D^2_p\epsilon^3}+1.75\frac{u_0^2L(1-\epsilon)}{D_p\epsilon^3}$

Where,

$u_0 =$ Superficial velocity of fluid

$\mu =$ Fluid viscoisty

$\epsilon =$ Porosity

$\rho =$ Fluid density

L = Packed bed length

$D_p$ = Effective particle diameter

Through energy balance equation we have that

$\Delta\frac{u^2}{2}+g\Delta z+\frac{\Delta p}{\rho}+w+F=0$

Neglect the change in velocity and pressure and the work done we have,

$g\Delta z+F = 0$

$g\Delta z+\frac{150u_0\mu L(1-\epsilon)^2}{\rho D^2_p\epsilon^3}+1.75\frac{u_0^2L(1-\epsilon)}{D_p\epsilon^3}=0$

$g\frac{\Delta z}{L}+\frac{150u_0\mu (1-\epsilon)^2}{\rho D^2_p\epsilon^3}+1.75\frac{u_0^2(1-\epsilon)}{D_p\epsilon^3}=0$

We have also that de grade is defined as

$tan\theta = \frac{\Delta z}{L}$

$tan\theta = 0.03$

With our values and replacing at the previous equation we have,

$(32.17)(-0.03)+\frac{150u_0(0.000672) (1-0.42)^2}{62.3 (0.417)^2 (0.42)^3}+1.75\frac{u_0^2(1-0.42)}{(0.417)(0.42)^3}=0$

$32.85u_0^2+0.04225u_0-0.9651=0$

$u_0 = 0.171ft/s$

Previously with the given depth and height we have to

$A=4*8$

$A=32ft^2$

Therefore the Volumetric flow rate,

$Q=u_0A$

$Q=(0.171ft/s)(32ft^2)(60s/1min)(1gal/0.133681ft^3)$

$Q= 2456gal/min$

Therefore the desired volumetric flow rate is 2456gal/min

4 0

3 years ago

A copper wire of original diameter .80 m exhibits a maximum tensile load/ strength at an engineering stress= 248.2 mpa. its duct

ddd [48]

Answer:

True Strain at failure = 1.386

Explanation:

For the question, ductility is given in reduction In the area to be 0.75

Let the initial Cross sectional Area of wire be Ao

And the final cross sectional Area of wire of cross sectional Area of wire at fracture be A

(Ao - A)/Ao = ductility = 0.75

Ao - A = 0.75Ao

A = Ao - 0.75Ao

A = 0.25 Ao

True Strain = In (Lf/Lo)

To obtain the ratio of the lengths of wire,

The volume of the wire stays constant, that is, Vo = Vf; Vo = Ao × Lo and Vf = A × Lf

AoLo = ALf

Lf/Lo = Ao/A

In (Lf/Lo) = In (Ao/A) = In (Ao/0.25Ao) = In 4 = 1.386

True Strain = 1.386

4 0

3 years ago

What could I do to make this bridge hold more weight without making it heavier? Lateral bracing and a design on the top will be

antoniya [11.8K]

Answer:

How to make a curved wooden Mincraft bridge you ask?

Making a simple wooden bridge requires you wood and some pieces of stone.

Explanation:

Hope this helps

7 0

2 years ago

The speed of an aircraft is given to be 260 m/s in air. If the speed of sound at that location is 330 m/s, the flight of the air

navik [9.2K]

Answer:

$Ma=\frac{260}{330} \\Ma=0.7878$

So, Ma < 1 Flow is Subsonic

Explanation:

Mach Number:

Mach Number is the ratio of speed of the object to the speed of the sound. It is used to categorize the speed of the object on the basis of mach number as sonic, supersonic and hyper sonic. (It is a unit less quantity)

Mach < 1 Subsonic

Mach > 1 Supersonic

Ma= Speed of the object/Speed of the sound

$Ma=\frac{260}{330} \\Ma=0.7878$

So, Ma < 1 Flow is Subsonic

8 0

3 years ago