Type the correct answer in the box. Spell all words correctly.

Goshia [24]

The answer would be 7

3 0

4 years ago

Carbon dioxide (CO2) is compressed in a piston-cylinder assembly from p1 = 0.7 bar, T1 = 320 K to p2 = 11 bar. The initial volum

tekilochka [14]

Answer:

$W_{12}=-53.9056KJ$

Part A:

$Q=-7.03734 KJ/Kg$ (-ve sign shows heat is getting out)

Part B:

$Q=1.5265KJ/Kg$ (Heat getting in)

The value of Q at constant specific heat is approximately 361% in difference with variable specific heat and at constant specific heat Q has opposite direction (going in) than Q which is calculated in Part B from table A-23. So taking constant specific heat is not a good idea and is questionable.

Explanation:

Assumptions:

Gas is ideal
System is closed system.
K.E and P.E is neglected
Process is polytropic

Since Process is polytropic so $W_{12} =\frac{P_{2}V_{2}-P_{1}V_{1}}{1-n}$

Where n=1.25

Since Process is polytropic :

$\frac{V_{2}}{V_{1}}=(\frac{P_{1}}{P_{2}})^{\frac{1}{1.25}} \\V_{2}= (\frac{P_{1}}{P_{2}})^{\frac{1}{1.25}} *V_{1}$

$V_{2}= (\frac{0.7}{11})^{\frac{1}{1.25}} *0.262\\V_{2}=0.028924 m^3$

Now, $W_{12} =\frac{P_{2}V_{2}-P_{1}V_{1}}{1-n}$

$W_{12} =\frac{11*0.028924-0.7*0.262}{1-1.25}(\frac{10^{5}N/m^2}{1 bar})(\frac{1 KJ}{10^{3}Nm})$

$W_{12}=-53.9056KJ$

We will now calculate mass (m) and Temperature T_2.

$m=\frac{P_{1}V_{1}}{RT_{1}}\\ m=\frac{0.7*0.262}{\frac{8.314KJ}{44.01Kg.K}*320}(\frac{10^{5}N/m^2}{1 bar})(\frac{1 KJ}{10^{3}Nm})\\m=0.30338Kg$

$T_{2} =\frac{P_{2}V_{2}}{Rm}\\ m=\frac{11*0.028924}{\frac{8.314KJ}{44.01Kg.K}*0.30338}(\frac{10^{5}N/m^2}{1 bar})(\frac{1 KJ}{10^{3}Nm})\\T_{2} =555.14K$

Part A:

According to energy balance::

$Q=mc_{v}(T_{2}-T_{1})+W_{12}$

From A-20, C_v for Carbon dioxide at 300 K is 0.657 KJ/Kg.k

$Q=0.30338*0.657(555.14-320)+(-53.9056)$

$Q=-7.03734 KJ/Kg$ (-ve sign shows heat is getting out)

Part B:

From Table A-23:

$u_{1} at 320K = 7526 KJ/Kg$

$u_{2} at 555.14K = 15567.292$ (By interpolation)

$Q=m(\frac{u(T_{2})-u(T_{1})}{M} )+W_{12}$

$Q=0.30338(\frac{15567.292-7526}{44.01} )+(-53.9056)$

$Q=1.5265KJ/Kg$ (Heat getting in)

The value of Q at constant specific heat is approximately 361% in difference with variable specific heat and at constant specific heat Q has opposite direction (going in) than Q which is calculated in Part B from table A-23. So taking constant specific heat is not a good idea and is questionable.

7 0

4 years ago

PLEASE HELP

Anna11 [10]

PLEASE HELP
NASA scientists have determined that the chance a single person would get hit by a piece of falling satellite is one in 3,200. What can you infer based on this probability?

A. Satellites that enter Earth’s atmosphere land mostly in the ocean.

B. NASA does a good job informing people of when satellites will enter the atmosphere.

C. Satellites that enter Earth’s atmosphere land mostly in unpopulated areas.

D. Much of a satellite is destroyed during the process of entering Earth’s atmosphere.

8 0

3 years ago

Read 2 more answers

Explain all the characteristics of computer<br>

Sedaia [141]

They are as follows-

Speed
Accuracy
Storage
Versatility
Diligence
Automation
Reliability
Power of Remembering

Let us understand each characteristic in brief:-

Speed – Speed of a computer means the time it takes to complete any given task. The computer works at a very lightning speed. For example, a computer takes a second to calculate 3 million calculations rather than a human which takes years. Hence nowadays the speed of the computer is measured in terms of microseconds, Nanoseconds, and even in Pico seconds instead of seconds or milliseconds.

Accuracy – The computers are programmed and designed in such a manner that their results are almost 100% accurate. It performs all the tasks with the same accuracy. There are very few chances of uncertainty in results and even though an error occurs, it can happen either due to wrong input data or unreliable programs by a programmer. Such errors are referred to as Garbage In Garbage Out (GIGO) which means, if you provide wrong instructions to the computer then you get wrong results.

Versatility – Along with being accurate and diligent a computer is also a versatile device. It can perform several types of tasks at a time if they are reduced to a certain set of logical steps. A computer can be used for many purposes at different places such as booking air and rail tickets, weather forecasting, listening to music, and playing games. Also at a time, one can pay his utility bills and can make a monthly budget too. It can prepare documents, data sheets and also can make models of houses, dams, etc.
Diligence – The ability of a computer to perform tasks without getting tired is known as diligence. Computers are highly reliable, they do not get fed up, exhausted, or lack concentration. They can work for hours and hours unlike humans and can give accurate or error-free results. For example, humans will start feeling tired after 2 -3 hours and will lack concentration whereas a computer will keep on working until the results are achieved.
Automation – Automation means working automatically. A computer can work on its own without the intervention of the person using it. Programs can be made for the computer to perform the task and based on the sequence it executes the tasks and gives accurate results. In case an error occurs, it gives error messages too and registers the logs.
Reliability – High reliability of a computer depends on low failure rate and easy maintenance. The results given out by the computer are reliable as the accuracy is almost 100%.
Power of Remembering – The computer has the power of storing data or information for several years. It cannot lose the data on its own. A person can retrieve the data whenever required and the data remains the same after a number of years also. It gives the freedom to the user to decide on how much data to store and how much to remove.

5 0

3 years ago

In crash tests, a shock absorber is used to slow the test car. The shock absorber consists of a piston with small holes that mov

Lesechka [4]

Answer:

The heat transferred to water equals 1600 kJ

Explanation:

By the conservation of energy we have

All the kinetic energy of the moving vehicle is converted into thermal energy

We know that kinetic energy of a object of mass 'm' moving with a speed of 'v' is given by

$K.E=\frac{1}{2}mv^{2}$