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3 years ago

Select the statement that is false.

Engineering

1 answer:

ra1l [238]3 years ago

8 0

Answer:

Explanation:

the way vertices are connected may be different so having same number of edges do not mean that total degree will also be same.

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Is santa real or nah is santa real or nah

Elena L [17]

Answer:

nah

Explanation:

3 0

3 years ago

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Two balanced Y-connected loads in parallel, one drawing 15kW at 0.6 power factor lagging and the other drawing 10kVA at 0.8 powe

NemiM [27]

Answer:

(a) attached below

(b) $pf_{C}=0.85$ $lagging$

(d) $X_{C} =49.37$ Ω

(e) $I_{cap} =9.72 A$ and $I_{line} =27.66 A$

Explanation:

Given data:

$P_{1}=15 kW$

$S_{2} =10 kVA$

$pf_{1} =0.6$ $lagging$

$pf_{2}=0.8$ $leading$

$V=480$ $Volts$

(a) Draw the power triangle for each load and for the combined load.

$\alpha_{1}=cos^{-1} (0.6)=53.13$ °

$\alpha_{2}=cos^{-1} (0.8)=36.86$ °

$S_{1}=P_{1} /pf_{1} =15/0.6=25 kVA$

$Q_{1}=P_{1} tan(\alpha_{1} )=15*tan(53.13)=19.99$ ≅ $20kVAR$

$P_{2} =S_{2}*pf_{2} =10*0.8=8 kW$

$Q_{2} =P_{2} tan(\alpha_{2} )=8*tan(-36.86)=-5.99$ ≅ $-6 kVAR$

The negative sign means that the load 2 is providing reactive power rather than consuming

Then the combined load will be

$P_{c} =P_{1} +P_{2} =15+8=23 kW$

$Q_{c} =Q_{1} +Q_{2} =20-6=14 kVAR$

(b) Determine the power factor of the combined load and state whether lagging or leading.

$S_{c} =P_{c} +jQ_{c} =23+14j$

or in the polar form

$S_{c} =26.92$ °

$pf_{C}=cos(31.32) =0.85$ $lagging$

The relationship between Apparent power S and Current I is

$S=VI^{*}$

Since there is conjugate of current I therefore, the angle will become negative and hence power factor will be lagging.

Current of the combined load can be found by

$I_{C} =S_{C}/\sqrt{3}*V$

$I_{C} =26.92*10^3/\sqrt{3}*480=32.37 A$

(d) Δ-connected capacitors are now installed in parallel with the combined load. What value of capacitive reactance is needed in each leg of the A to make the source power factor unity?Give your answer in Ω

$Q_{C} =3*V^2/X_{C}$

$X_{C} =3*V^2/Q_{C}$

$X_{C} =3*(480)^2/14*10^3$ Ω

(e) Compute the magnitude of the current in each capacitor and the line current from the source.

Current flowing in the capacitor is

$I_{cap} =V/X_{C} =480/49.37=9.72 A$

Line current flowing from the source is

$I_{line} =P_{C} /3*V=23*10^3/3*480=27.66 A$

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3 years ago

Counter argument for why engineers dont make a positive change in the world.

egoroff_w [7]

Answer:

They don't make a positive change in the world because they have made mistakes that aren't able to be made fixed and there are a lot of engineers who haven't study enough and know the important basis of coming to engineer.

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3 years ago

How buy airpods in my phone

Levart [38]

U mean how to connect them to your phone?

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3 years ago

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Write a program that uses the function isPalindrome given below. Test your program on the following strings: madam, abba, 22, 67

defon

Answer:

#include <iostream>

#include <string>

using namespace std;

bool isPalindrome(string str)

{

int length = str.length();

for (int i = 0; i < length / 2; i++)

{

if (tolower(str[i]) != tolower(str[length - 1 - i]))

return false;

}

return true;

}

int main()

{

string s[6] = {"madam", "abba", "22", "67876", "444244", "trymeuemyrt"};

int i;

for(i=0; i<6; i++)

{

//Testing function

if(isPalindrome(s[i]))

{

cout << "\n " << s[i] << " is a palindrome... \n";

}

else

{

cout << "\n " << s[i] << " is not a palindrome... \n";

}

return 0;

}

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3 years ago