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3 years ago

Select the correct answer.

Engineering

2 answers:

FrozenT [24]3 years ago

6 0

Answer:

B. Italy

Explanation:

Hope this helps :)

nadezda [96]3 years ago

3 0

The answer is B) Italy

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A 3-phase induction motor with 4 poles is being driven at 45 Hz and is running in its normal operating range. When connected to

Dennis_Churaev [7]

Answer:

a) The slip for the given conditions is 0.2074 or 20.74% and the developed torque is 7.14 Nm.

b) The new slip after reducing the torque to 4 Nm is 0.1162 or 11.62% and the new motor speed is 1193.13 rpm.

Explanation:

In order to find the slip we can use the definition as the relative difference between Synchronous speed and the rotor speed and that the developed torque is the ratio between output power and rotor angular velocity.

Slip.

We can find the synchronous speed u sing the following formula

$N_s =\cfrac{120f}p$

Where f stands for the frequency and p the number of poles, so we have

$N_s = \cfrac{120(45)}{4}\\N_s =1350 \,rpm$

Replacing on the slip formula

$S = \cfrac{N_s-N_r}{N_s}$

we get

$S = \cfrac{1350-1070}{1350}\\ S = 0.2074$

Thus the slip for the given conditions is 0.2074 or 20.74%.

Developed torque.

We can find the angular velocity in radians per second

$\omega_r =1070 \cfrac{rev}{min} \times \cfrac{1 \, min}{60 \, s}\times \cfrac{2\pi rad}{1 \, rev}\\\omega_r =112.05 \, \cfrac{rad}{s}$

Thus we can replace on the torque formula

$\tau = \cfrac{P}{\omega_r}\\\tau=\cfrac{800 W}{112.05 \, \cfrac{rad}{s}}$

We get

$\tau = 7.14\, N m$

The developed torque is 7.14 Nm.

Slip for the reduced torque.

The torque is proportional to the slip, so we can write

$\cfrac{\tau_1}{\tau_2}= \cfrac{S_1}{S_2}$

Thus solving for the new slip $S_2$ we have:

$S_2 = S_1 \cfrac{\tau_2}{\tau_1}$

Replacing the values obtained on the previous part we have

$S_2 = 0.2074 \cfrac{4 Nm}{7.14 Nm}\\ S_2=0.1162$

So the new slip after reducing the torque to 4 Nm is 0.1162 or 11.62%

Motor speed.

We can use the slip definition

$S_2 =\cfrac{N_s-N_{r_2}}{N_s}$

Solving for the motor speed we have

$S_2N_s =N_s-N_{r_2}$

$N_{r_2}=N_s-S_2N_s \\N_{r_2}=N_s(1-S_2)$

Replacing values we have

$N_{r_2}=1350 \, rpm(1-0.1162)\\N_{r_2}=1193.13 rpm$

The new motor speed is 1193.13 rpm.

5 0

3 years ago

You have designed a treatment system for contaminant Z. The treatment system consists of a pipe that feeds into a CSTR. The pipe

IRISSAK [1]

Answer:

0.667 per day.

Explanation:

Our values here are

$Q=10m^3/dV_p=15m^3\\V_{cstr}=60m^3\\c_p=2500mg/L\\c_{cstr}=500mg/L$

Degradation constant=k and is unknown.

We calculate the concentration through the formula,

$cc_{cstr} =\frac{c_{in}}{1+K(V/Q)} \\cc_{cstr}=\frac{c_p}{1+K*\frac{V_{csrt}}{Q}}$

Replacing values we have

$1+k(\frac{60}{10})=\frac{2500}{500}\\1+k=5\\K(6)=5-1\\K(6)=4\\K=2/3\\K=0.667/day$

That is the degradation constant of Z-contaminant

3 0

3 years ago

A slab-milling operation is performed on a 0.7 m long, 30 mm-wide cast-iron block with a feed of 0.25 mm/tooth and depth of cut

denis23 [38]

Answer:

a) $T_m=1.787min$

b) $MRR=35259.7mm^3/min$

Explanation:

From the question we are told that:

Cast-iron block Dimension:

Length $l=0.7m=>700mm$

Width $w=30mm$

Feed $F=0.25mm/tooth$

Depth $dp=3mm$

Diameter $d=75mm$

Number of cutting teeth $n=8$

Rotation speed $N=200rpm$

Generally the equation for Approach is mathematically given by

$x=\sqrt{Dd-d^2}$

$X=\sqrt{75*3-3^2}$

$X=14.69mm$

Therefore

Effective length is given as

$L_e=Approach +object Length$

$L_e=700+14.69$

$L_e=714.69mm$

Generally the equation for Machine Time is mathematically given by

$T_m=\frac{L_e}{F_m}$

Where

$F_m=F*n*N$

$F_m=0.25*8*200$

$F_m=400$

Therefore

$T_m=\frac{714.69}{400}$

$T_m=1.787min$

Generally the equation for Material Removal Rate. is mathematically given by

$MRR=\frac{L*B*d}{t_m}$

$MRR=\frac{700*30*3}{1.787}$

$MRR=35259.7mm^3/min$

3 0

3 years ago

A tensile test is performed on a metal specimen, and it is found that a true plastic strain of 0.20 is produced when a true stre

disa [49]

Answer:

0.234

Explanation:

True stress is ratio of instantaneous load acting on instantaneous cross-sectional area

σ = k × (ε)^n

σ = true stress

ε = true strain

k = strength coefficient

n = strain hardening exponent

ε = ( σ / k) ^1/n

take log of both side

log ε = $\frac{1}{n}$ ( log σ - log k)

n = ( log σ - log k) / log ε

n = (log 578 - log 860) / log 0.20 = 0.247

the new ε = ( 600 / 860)^( 1 / 0.247) = 0.234

6 0

3 years ago

Read 2 more answers

Your manager has asked you to research and recommend a writing guide that examiners in your digital forensics company can use fo

vivado [14]

Answer:

Kindly Check the explanation

Explanation:

Report

A Report is a way to present the forensic examination result in front of judge. A report contains warrants, all affidavits issued for arrest, expenses occur during forensic test and lists of evidence. Apart from evidence a report also contains expert opinions.

Guidelines

These are the set of rules and written statement which are used to present the important information in a structured and clear format. The main motive behind to define the guidelines is to achieve standardization in the reports. It also improves the readability of the report.

Guidelines for report

Abstract:

Each report must contain an abstract of the report which gives the brief review about the report. It came at the starting of the report. The main motive behind to give abstract is to give brief about report to someone in a very less time. The size of abstract must not be more than one page.

Index:

Each report must contain an index which display's which content is available at which page of report. The content of index must be appropriate and clear so that the reader will not get confuse.

Format of report:

The formatting of report is also one of the essential parts of the guidelines. It makes the report attractive and also due to this reader not gets bored while reading the report. The guidelines regarding layout of report are as follow:

1. Use time roman font and 12 font size as a default font to explain anything in the report.

2. The explanation must be justified

3. As possible divide the long paragraph. if possible explain in points.

4. The page must have border on all sides

5. Each pages must have numbering and footer

Rules for grammar:

1. The language of the report must be simple and clear. So that everyone can understand it easily.

2. Avoid repeating same sentence or word again and again.

3. Use active instead of passive voice, in order to give importance to doer.

4. Write expressions between commas.

5. Avoid spelling mistakes in report which also make wrong impact.

6. As possible give heading or subheading to material or explanation which must be accurate.

7. Explain, new or difficult words used in the report.

8. What ever written in the report must be through the point and accurate on bases of fact.

Body of report:

The body of the report referred to as a content written inside the report. In order to write an impressive report, it must include all these things:

1. Avoid use of hypothetical question, if still hypothetical question arises it must be bases on factual evidence.

2. Add all the affidavits and warrants in the report issued for search and arrest.

3. The cost money expenses while solving the case.

4. The expert opinion which must be bases on knowledge or previously declare case results.

5. The list of people and evidence which are collected and interrogative during the investigation.

6. If investigation is further going on than write the area in which the investigation further goes on and also mention when the investigation get complete.

Forensic software used:

A short must be given about the software used in the investigation. The result generated by the software must also be pasted in that report. It is more good if attach the snap shot of the result. Add any previous case result in which the same software result is taken as evidence, in order to justify that the result generated by the software is true. Some of forensic softwares are FTK, ProDiscover, Hexworkshop. The result of these softwares must be heighted so that everyone can notice it.

Conclusion:

The conclusion must be given at the end of report to tell according him what result came after investigation. In conclusion also write on which basis the result concludes. There must be strong behind the conclusion.

References:

In Reference write all the cases, thesis, books which an investigator followed to solve the current case. In addition if they referred any internet article. They can also write the website name where that article lies. In short can say that write everything where they got an idea which is helpful in solving the case.

8 0

3 years ago