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3 years ago

14

Vacancy diffusion statement refer to that a mechanism that

1 answer:

belka [17]3 years ago

4 0

Answer:

true

Explanation:

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Consider steady heat transfer through the wall of a room in winter. The convection heat transfer coefficient at the outer surfac

AveGali [126]

The heat transfer which is in steady state, the heat transfer rate to the wall is equal to the wall.

<u>Explanation:</u>

The convection transfer of heat to the wall is

$Q=h A\left(T_{s}-T_{f}\right)$

Here, $T_{S}$ is the temperature of solid surface, $T_{f}$ is the temperature of moving fluid stream which is adjacent of solid surface, h is the heat transfer coefficient.
The coefficient of convection heat transfers outer surface contains 3 times to the inner surface which experience smaller drop of temperature for 3 times that compares to inner surface.
Hence, the temperatures outer surface get close to the surroundings of air temperature.

6 0

3 years ago

The acceleration of a particle is given by a = 2t − 10, where a is in meters per second squared and t is in seconds. Determine t

tensa zangetsu [6.8K]

Answer

given,

a = 2 t - 10

velocity function

we know,

$\dfrac{dv}{dt}=a$

$\dfrac{dv}{dt}=(2t-10)$

integrating both side

$\int dv =\int (2t -10) dt$

v = t² - 10 t + C

at t = 0 v = 3

so, 3 = 0 - 0 + C

C = 3

Velocity function is equal to v = t² - 10 t + 3

Again we know,

$\dfrac{dx}{dt}=v$

$\dfrac{dx}{dt}=(t^2-10t + 3)$

integrating both side

$\int dx =\int (t^2-10t + 3)dt$

$x = \dfrac{t^3}{3}- 10\dfrac{t^2}{2} + 3 t + C$

now, at t= 0 s = -4

$-4 = \dfrac{0^3}{3}- 10\dfrac{0^2}{2} + 0 + C$

C = -4

So,

$x = \dfrac{t^3}{3}- 10\dfrac{t^2}{2} + 3 t-4$

Position function is equal to $x = \dfrac{t^3}{3}- 10\dfrac{t^2}{2} + 3 t-4$

8 0

4 years ago

A 75 mm diameter, 15 mm wide A80-M12V grinding wheel is used for traverse surface grinding of a 75 mm by 75 mm 1040 steel workpi

Dmitrij [34]

Answer:

Detailed solution is given and calculations are done

3 0

3 years ago

How do we need to prepare for the future?

Paraphin [41]

B. to achieve sustainable development

5 0

3 years ago

External crack of length of 3.0 mm was detected on the surface of the shaft of wind turbine made from 4340 steel. The diameter o

sveticcg [70]

Answer:

The correct answer is " $K_c=6.0369 \ MPa\sqrt{m}$ ".

Explanation:

Given:

Maximum load,

P = 50,000 N

Crack length,

a = 3mm

or,

= 3×10⁻³ m

Diameter,

d = 32 mm

As we know,

⇒ Maximum stress, $\sigma=\frac{P}{A}$

$=\frac{50000}{(\frac{\pi}{4}\times 32^2)}$

$=62.20 \ N/mm^2$

Now,

⇒ Fracture tougness, $K_c=Y \sigma\sqrt{\pi a}$

On substituting the values, we get

$=1\times 62.20\times \sqrt{3.14\times 3\times 10^{-3}}$

$=6.0369 \ MPa\sqrt{m}$

4 0

3 years ago