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3 years ago

For three control stations,there should be how many start buttons in parallel with the suxiliary contact

1 answer:

6 0

The three load contacts connected between the three-phase power line and the motor close to connect the motor to the line. The normally open auxiliary contact connected in parallel with the two Start buttons closes to maintain the circuit to M coil when the Start button is released.

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Tin atoms are introduced into an FCC copper ,producing an alloy with a lattice parameter of 4.7589×10-8cm and a density of 8.772

slega [8]

Answer:

atomic percentage = 143 %

Explanation:

Let x be the number of tin atoms and there are 4 atoms / cell in the FCC structure , then 4 -x be the number of copper atoms . Therefore, the value of x can be determined by using the density equation as shown below:

$\mathbf{density (\rho) = \dfrac{(no \ of \ atoms/cell)(atomic \ mass )}{(lattice \ parameter )^3(6.022*10^{23} atoms/ mol)} }$

where;

the lattice parameter is given as : 4.7589 × 10⁻⁸ cm

The atomic mass of tin is 118.69 g/mol

The atomic mass of copper is 63.54 g/mol

The density is 8.772 g/cm³

$\mathbf{8.772 g/cm^3 = \dfrac{(x)(118.69 \ g/mol) +(4-x)(63.54 \ g/mol)}{(4.7589*10^{-8} cm )^3(6.022*10^{23} atoms/ mol)} }$

569.32 = 118.69x + 254.16-63.54x

569.32 - 254.16 = 118.69x - 63.54 x

315.16 = 55.15x

x = 315.16/55.15

x = 5.72 atoms/cell

As there are four atoms per cell in FCC structure for the metal, thus, the atomic percentage of the tin is calculated as follows :

atomic % = $\frac{no \ of \ atoms \ per \ cell \ in \ tin }{no \ of \ atoms \ per \ cell \ in \ the \ metal}*100$

atomic % = $\frac{5.72 \ atoms / cell}{4 \ atoms/ cell} *100$

atomic % = 143 %

7 0

3 years ago

For a turning operation, you have selected a high-speed steel (HSS) tool and turning a hot rolled free machining steel. Your dep

Alisiya [41]

Answer:

MRR = 1.984

Explanation:

Given that

Depth of cut ,d=0.105 in

Diameter D= 1 in

Speed V= 105 sfpm

feed f= 0.015 ipr

Now the metal removal rate given as

MRR= 12 f V d

d= depth of cut

V= Speed

f=Feed

MRR= Metal removal rate

By putting the values

MRR= 12 f V d

MRR = 12 x 0.015 x 105 x 0.105

MRR = 1.984

Therefore answer is -

1.944

8 0

3 years ago

The following is a correlation for the average Nusselt number for natural convection over spherical surface. As can be seen in t

vovikov84 [41]

Answer:

Explanation:

$r_2=$ ∞

$q=4\pi kT_1(T_2-T_1)\\$

$q=2\pi kD.$ ΔT--------(1)

$q=hA$ ΔT $=4\pi r_1^2(T_2_s-T_1_s)\\$

$N_u=\frac{hD}{k} = 2+\frac{0.589 R_a^\frac{1}{4} }{[1+(\frac{0.046}{p_r}\frac{9}{16} )^\frac{4}{9} } ------(3)$

By equation (1) and (2)

$2\pi kD.$ ΔT=h.4 $\pi r_1^2$ ΔT

$2kD=hD^2\\\frac{hD}{k} =2\\N_u=\frac{hD}{k}=2\\$ -------(4)

From equation (3) and (4)

So for sphere $R_a$ →0

6 0

3 years ago

How do engineering and technology impact the natural world and environment

ddd [48]

Answer:

Answer to the following question is as follow.

Explanation:

Civil engineering industrial development projects have a significant influence on the environment, particularly in terms of excessive noise, environmental pollution, and land shrinkage.

Engineers have totally transformed our environment, from contemporary dwellings to bridges, space flight, automobiles, and cutting-edge mobile technologies. Engineers utilise their expertise to build new and exciting prospects and address any difficulties that may occur, and they employ their innovative ideas to accomplish so.

8 0

3 years ago

Which of the following types of protective equipment protects workers who are passing by from stray sparks or metal while anothe

natima [27]

Answer:

Fire/Flame resistant clothing and aprons

Explanation:

Individuals working with or around welding equipment are usually required to wear Fire/Flame resistant clothing and aprons which are designed to protect the user from various types of hazards including heat, fires , burns , and sometimes radiation. In this scenario, it would protect the individual from the welding sparks that are produced when welding, which tends to fly all over the place and can catch fire in some cases. These clothes will prevent that from happening.

7 0

3 years ago