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allsm [11]
3 years ago
9

A system executes a power cycle while receiving 1000 kJ by heat transfer at a temperature of 500 K and discharging 700 kJ by hea

t transfer at a temperature of 300 K. There are no other heat transfers. Determine the cycle efficiency. Use the Clausius Inequality to determine , in kJ/K. Determine if this cycle is internally reversible, irreversible, or impossible.
Engineering
1 answer:
Ghella [55]3 years ago
8 0

Answer:

\eta_{th} = 30\,\%, \eta_{th,max} = 40\,\%, \Delta S = \frac{1}{3}\,\frac{kJ}{K}, The cycle is irreversible.

Explanation:

The real cycle efficiency is:

\eta_{th} = \frac{1000\,kJ-700\,kJ}{1000\,kJ} \times 100\,\%

\eta_{th} = 30\,\%

The theoretical cycle efficiency is:

\eta_{th,max} = \frac{500\,K-300\,K}{500\,K} \times 100\,\%

\eta_{th,max} = 40\,\%

The reversible and real versions of the power cycle are described by the Clausius Inequalty:

Reversible Unit

\frac{1000\,kJ - 600kJ}{300\,K}= 0

Real Unit

\Delta S = \frac{1000\,kJ-600\,kJ}{300\,K} -\frac{1000\,kJ-700\,kJ}{300\,K}

\Delta S = \frac{1}{3}\,\frac{kJ}{K}

The cycle is irreversible.

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Match each term in the second column with its correct definition in the first column.
Levart [38]

Answer:

The filled in the black answers is:

1. work book

2. Spreadsheet

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4. Sheet tabs

5. Column

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7 0
3 years ago
Java Programming: Loops and Conditionals
velikii [3]

Answer:

  1. import java.util.Scanner;
  2. import java.util.Random;
  3. public class Main {
  4.    public static void main(String[] args) {
  5.        Scanner input = new Scanner(System.in);
  6.        Random rand = new Random();
  7.        System.out.print("Enter number of questions you wish to practice: ");
  8.        int n = input.nextInt();
  9.        int i = 1;
  10.        while(i <= n){
  11.            int num1 = 1 + rand.nextInt(10);
  12.            int num2 = 1 + rand.nextInt(10);
  13.            int answer = num1 * num2;
  14.            System.out.print("Question " + i + ": " + num1 + " x " + num2 + " = ");
  15.            int response = input.nextInt();
  16.            if(response == answer){
  17.                System.out.println("Correct answer!");
  18.            }
  19.            else{
  20.                System.out.println("Wrong answer. It should be " + answer);
  21.            }
  22.            i++;
  23.        }
  24.    }
  25. }

Explanation:

Firstly, we import Scanner and Random classes (Line 1-2) as we need to get user input for number of questions and generate random number in each question.

Next, create a Scanner and Random object (Line 7-8).  Prompt user to input number of question and get the input using the Scanner object (Line 10-11).

Next create a while loop and set the condition to loop for n number of times (based on number of questions) (Line 14). In the loop, use Random object nextInt method to generate two integers between 1 -10 (Line 15-16). Prompt user to input an answer using the Scanner object (Line 18-19). If the response is matched with answer print a correct message (Line 21-22) other wise inform user they write a wrong answer and show the correct answer (Line 24-25).

8 0
4 years ago
Which of the following is true regarding screw gauges and shank?
agasfer [191]
correct me if i’m wrong i’m pretty sure it’s B i’ve had the same question
6 0
3 years ago
Various factors to be considered in deciding the factor of safety?
Eduardwww [97]

Answer with Explanation:

There are various factors that needed to be taken into account while deciding the factor of safety some of which are summarized below as:

1) Importance of the structure: When we design any structure different structures have different importance in our society. Take an example of hospital, in case a natural disaster struck's a place the hospital should be the designed to withstand the disaster as it's role in the crisis management following a disaster is well understood. Thus while designing it we need it to have a higher factor of safety against failure when compared to a local building.

2) Errors involved in estimation of strength of materials: when we design any component of any machine or a structure we need to have an exact idea of the behavior of the material and know the value of the strength of the material. But many materials that we use in structure such as concrete in buildings have a very complex behavior and we cannot estimate the strength of the concrete absolutely, thus we tend to decrease the strength of the concrete more if errors involved in the estimation of strength are more to give much safety to the structure.

3) Variability of the loads that may act on the structure: If the loads that act on the structure are highly variable such as earthquake loads amd dynamic loads then we tend to increase the factor of safety while estimating the loads on the structure while designing it.

4) Economic consideration: If our project has abundant funds then we can choose a higher factor of safety while designing the project.

4 0
3 years ago
Consider a thin suspended hotplate that measures 0.25 m × 0.25 m. The isothermal plate has a mass of 3.75 kg, a specific heat of
Orlov [11]

Answer:

Heat losses by convection, Qconv = 90W

Heat losses by radiation, Qrad = 5.814W

Explanation:

Heat transfer is defined as the transfer of heat from the heat surface to the object that needs to be heated. There are three types which are:

1. Radiation

2. Conduction

3. Convection

Convection is defined as the transfer of heat through the actual movement of the molecules.

Qconv = hA(Temp.final - Temp.surr)

Where h = 6.4KW/m2K

A, area of a square = L2

= (0.25)2

= 0.0625m2

Temp.final = 250°C

Temp.surr = 25°C

Q = 64 * 0.0625 * (250 - 25)

= 90W

Radiation is a heat transfer method that does not rely upon the contact between the initial heat source and the object to be heated, it can be called thermal radiation.

Qrad = E*S*(Temp.final4 - Temp.surr4)

Where E = emissivity of the surface

S = boltzmann constant

= 5.6703 x 10-8 W/m2K4

Qrad = 5.6703 x 10-8 * 0.42 * 0.0625 * ((250)4 - (25)4)

= 5.814 W

7 0
4 years ago
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