A household refrigerator that has a power input of 450 W and a COP of 1.5 is to cool 5 large watermelons, 10 kg each, to 8 C. If the watermelons are initially at 28 C, determine how long it will take for the refrigerator to cool them.

Answers

Answer 1
Answer:

Answer:

\Delta t = 5866.667\,s\,(97.778\,m)

Explanation:

The specific heat for watermelon above freezing point is 3.96\,(kJ)/(kg\cdot K). The heat liberated by the watermelon to cool down to 8°C is:

Q_(cooling) = (5)\cdot (10\,kg)\cdot (3.96\,(kJ)/(kg\cdot K) )\cdot (20\,K)

Q_(cooling) = 3960\,kJ

The heat absorbed by the household refrigerator is:

\dot Q_(L) = COP\cdot \dot W_(e)

\dot Q_(L) = 1.5\cdot (0.45\,kW)

\dot Q_(L) = 0.675\,kW

Time needed to cool the watermelons is:

\Delta t = (Q_(cooling))/(\dot Q_(L))

\Delta t = (3960\,kJ)/(0.675\,kW)

\Delta t = 5866.667\,s\,(97.778\,m)

 


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A cylindrical specimen of a hypothetical metal alloy is stressed in compression. If its original and final diameters are 20.000 and 20.025 mm, respectively, and its final length is 74.96 mm, compute its original length if the deformation is totally elastic. The elastic and shear moduli for this alloy are 105 GPa and 39.7 GPa, respectively.

Answers

Answer:

L = 75.25 mm

Explanation:

First we need to find the lateral strain:

Lateral Strain = Change in Diameter/Original Diameter

Lateral Strain = (20.025 mm - 20 mm)/20 mm

Lateral Strain = 1.25 x 10⁻³

Now, we will find the Poisson's Ratio:

Poisson's Ratio = (E/2G) - 1

where,

E = Elastic Modulus = 105 GPa

G = Shear Modulus = 39.7 GPa

Therefore,

Poisson's Ratio = [(105 GPa)/(2)(39.7 GPa)] - 1

Poisson's Ratio = 0.322

Now, we find longitudinal strain by following formula:

Poisson's Ratio = - Lateral Strain/Longitudinal Strain

Longitudinal Strain = - Lateral Strain/Poisson's Ratio

Longitudinal Strain = - (1.25 x 10⁻³)/0.322

Longitudinal Strain = - 3.87 x 10⁻³

Now, we can fin the original length:

Longitudinal Strain = Change in Length/L

where,

L = Original Length = ?

Therefore,

- 3.87 x 10⁻³ = (74.96 mm - L)/L

(- 3.87 x 10⁻³)(L) + L = 74.96 mm

0.99612 L = 74.96 mm

L = 74.96 mm/0.99612

L = 75.25 mm

Use Newton's method to determine the angle θ, between 0 and π/2 accurate to six decimal places. for which sin(θ) = 0.1. Show your work until you start computing x1, etc. Then just write down what your calculator gives you.

Answers

Answer:

x3=0.100167

Explanation:

Let's find the answer.

Because we are going to find the solution for sin(Ф)=0.1 then:

f(x)=sin(Ф)-0.1 and:

f'(x)=cos(Ф)

Because 0<Ф<π/2 let's start with an initial guess of 0.001 (x0), so:

x1=x0-f(x0)/f'(0)

x1=0.001-(sin(0.001)-0.1)/cos(0.001)

x1= 0.100000

x2=0.100000-(sin(0.100000)-0.1)/cos(0.100000)

x2=0.100167

x3=0.100167

) A flow is divided into two branches, with the pipe diameter and length the same for each branch. A 1/4-open gate valve is installed in line A, and a 1/3-closed ball valve is installed in line B. The head loss due to friction in each branch is negligible compared with the head loss across the valves. Find the ratio of the velocity in line A to that in line B (include elbow losses for threaded pipe fittings).

Answers

Answer:

Va / Vb = 0.5934

Explanation:

First step is to determine total head losses at each pipe

at Pipe A

For 1/4 open gate valve head loss = 17 *Va^2 / 2g

elbow loss = 0.75 Va^2 / 2g

at Pipe B

For 1/3 closed ball valve head loss = 5.5 *Vb^2 / 2g

elbow loss = 0.75 * Vb^2 / 2g

Given that both pipes are parallel

17 *Va^2/2g +  0.75*Va^2 / 2g = 5.5 *Vb^2 / 2g  + 0.75 * Vb^2 / 2g

∴ Va / Vb = 0.5934

Write a Lottery class that simulates a lottery. The class should have an array of five integers named lotteryNumbers. The constructor should use the Random class (from the Java API) to generate a random number in the range of 0 through 9 for each element in the array. The class should also have a method that accepts an array of five integers that represent a person’s lottery picks. The method is to compare the corresponding elements in the two arrays and return the number of digits that match. For example, the following shows the lotteryNumbers array and the user’s array with sample numbers stored in each. There are two matching digits (elements 2 and 4).

Answers

Answer:

Output:-

Enter the five digit lottery number

Enter the digit 1 : 23

Enter the digit 2 : 44

Enter the digit 3 : 43

Enter the digit 4 : 66

Enter the digit 5 : 33

YOU LOSS!!

Computer Generated Lottery Number :

|12|38|47|48|49|

Lottery Number Of user:

|23|33|43|44|66|

Number Of digit matched: 0

Code:-

import java.util.Arrays;

import java.util.Random;

import java.util.Scanner;

public class Lottery {

int[] lotteryNumbers = new int[5];

public int[] getLotteryNumbers() {

return lotteryNumbers;

}

Lottery() {

Random randomVal = new Random();

for (int i = 0; i < lotteryNumbers.length; i++) {

lotteryNumbers[i] = randomVal.nextInt((50 - 1) + 1);

}

}

int compare(int[] personLottery) {

int count = 0;

Arrays.sort(lotteryNumbers);

Arrays.sort(personLottery);

for (int i = 0; i < lotteryNumbers.length; i++) {

if (lotteryNumbers[i] == personLottery[i]) {

count++;

}

}

return count;

}

public static void main(String[] args) {

int[] personLotteryNum = new int[5];

int matchNum;

Lottery lnum = new Lottery();

Scanner input = new Scanner(System.in);

System.out.println("Enten the five digit lottery number");

for (int i = 0; i < personLotteryNum.length; i++) {

System.out.println("Enter the digit " + (i + 1) + " :");

personLotteryNum[i] = input.nextInt();

}

matchNum = lnum.compare(personLotteryNum);

if (matchNum == 5)

System.out.println("YOU WIN!!");

else

System.out.println("YOU LOSS!!");

System.out.println("Computer Generated Lottery Number :");

System.out.print("|");

for (int i = 0; i < lnum.getLotteryNumbers().length; i++) {

System.out.print(lnum.getLotteryNumbers()[i] + "|");

}

System.out.println("\n\nLottery Number Of user:");

System.out.print("|");

for (int i = 0; i < personLotteryNum.length; i++) {

System.out.print(personLotteryNum[i] + "|");

}

System.out.println();

System.out.println("Number Of digit matched: " + matchNum);

}

}

Explanation:

The following program includes fictional sets of the top 10 male and female baby names for the current year. Write a program that creates: A set all_names that contains all of the top 10 male and all of the top 10 female names. A set neutral_names that contains only names found in both male_names and female_names. A set specific_names that contains only gender specific names. Sample output for all_names: {'Michael', 'Henry', 'Jayden', 'Bailey', 'Lucas', 'Chuck', 'Aiden', 'Khloe', 'Elizabeth', 'Maria', 'Veronica', 'Meghan', 'John', 'Samuel', 'Britney', 'Charlie', 'Kim'}

Answers

The program analyses a set of male and female names and displays, the combined set of names, specific names and neutral names. The program written in python 3 goes thus :

male_names = {'John', 'Bailey', 'Charlie', 'Chuck', 'Michael', 'Samuel', 'Jayden', 'Aiden', 'Henry', 'Lucas'}

#setofmalenames

female_names = {'Elizabeth', 'Meghan', 'Kim', 'khloe','Bailey', 'Jayden' , 'Aiden', 'Britney', 'Veronica', 'Maria'}

#setoffemalenames

neutral_names = male_names.intersection(female_names)

#names common to both males and females

all_names = male_names.union(female_names)

#set of all baby names ; both male and female

specific_names = male_names.symmetric_difference(female_names)

#name in one set and not in the other

print(all_names)

print(' ')

#leavesaspaceinbetweenthelines

print(specific_names)

print(' ')

print(neutral_names)

Asamplerunoftheprogramisattached.

Learn more :brainly.com/question/9908895

Answer:

Please see attachment

Explanation:

Please see attachment

A technician has been dispatched to assist a sales person who cannot get his laptop to display through a projector. The technician verified the video is displaying properly on the laptop's built-in screen. Which of the following is the next step the technician should take?

Answers

Answer:verify proper cable is hooked between laptop and projector. HDMI ports or 15 pin video output to input.

And laptop is selected to output to respective video output.

Explanation: