Physics, 10.03.2020 00:30 corban13

Bituminous coal has a heat of combustion of 31.4 MJ/kg. In the United States the average coal-burning utility producesan average of 2.2 kWh of electrical energy per kilogram of bituminous coal burned. What is the average overall efficiency of this production of electricity

Answers: 2

Show answers

Answers

Answer from: chem64

The average overall efficiency of the production of electricity is 25.22%.

Given data:

The heat of combustion produced by the coal is, $Q =31.4 \;\rm MJ/kg = 31.4 \times 10^{3} \;\rm kJ/kg$ .

The average electric energy produced per kg is, $E = 2.2 \;\rm kWh = 2.2 \times 3600 = 7920 \;\rm kJ$ .

The given problem is based on the concept of overall efficiency. In general, it is general defined as the ratio of the energy produced and the heat of combustion due to burning of source (coal).

Then,

$\eta = \dfrac{E}{Q} \times 100 \%$

Solving as,

$\eta = \dfrac{7920 \;\rm kJ}{31.4 \times 10^{3} \;\rm kJ/kg} \times 100 \%\\\\\eta = 25.22 \%$

Thus, we can conclude that the average overall efficiency of the production of electricity is 25.22%.

Learn more about the overall efficiency here:

link

Answer from: sanfratello1081

$\eta = 25.223\,\%$

Explanation:

The average overall efficiency is given by the following expression:

$\eta = \frac{w}{q}\times 100 \%$

$\eta = \frac{(2.2\,kWh)\cdot (\frac{3600\,kJ}{1\,kWh} )}{31.4\times 10^{3}\,\frac{kJ}{kg}} \times 100\%$

$\eta = 25.223\,\%$

Answer from: Quest

given data:

determine the horse power (h.p) = ?

force applied to move the box(f) = 10 pounds,

box lifted from a distance (d) = 3 feet

time taken to lift (t) = 10 sec,

the horse power is defined as amount of work required to move a load. the horse power is equal to 550 foot-pound per second

1 h.p = 550 foot-pound/second

it can also be defined as the the load that need to be move a body for certain distance in a certain amount of time.

mathematically,

h.p = (force × distance)/ time

= (10 × 3)/ 10

= 30/10

= 3 foot -pound/sec

hence, the horse power is needed to move the box is 3 foot-pound/second

important note: 1 h.p = 550 foot-pound/second = 746 watts

Answer from: Quest

see the picture for the vector

the magnitude of the vector by pythagorean theorem

r = √( (-10)^2 + (3)^2 ) = √109

magnitude = √109 units

the direction angle between vector and x-axis is

tan^(-1)(3/10) = 16.699

so the direction is approximately 16.7 degrees north of west

Another question on Physics

Physics, 22.06.2019 12:30

Write a full page that sumerizes thermodynamics it’s from the website visionlearnig

Answers: 1

Answer

Physics, 22.06.2019 16:00

What is the measure of how much matter is in an object and that can be measured using a balance? a. height b. volume c. weight d. mass

Answers: 1

Answer

Physics, 22.06.2019 17:30

This chart shows characteristics of three different types of waves. which statement is best supported by the information in the chart? wave x and wave y are mechanical waves, and wave z is an electromagnetic wave. wave x and wave y are electromagnetic waves, and wave z is a mechanical wave. wave x and wave z are electromagnetic waves, and wave y is a mechanical wave. wave x and wave z are mechanical waves, and wave y is an electromagnetic wave.

Answers: 1

Answer

Physics, 22.06.2019 22:30

Isobars are lines of constant or equal pressure on a weather map. they can be used to find areas of low or high pressure over a broad area, and they can tell us how intense the system may be. on weather maps, you may have noticed areas that have a large l or h over a region with lines circling around them. the l stands for low pressure and h stands for high pressure. the lines circling them are isobars. check out the pressure system and isobars over georgia and florida. what is the present weather in this area ? a) clear and sunny b) cold and cloudy c) changing weather d) lots of precipitation

Answers: 3

Answer

You know the right answer?

Bituminous coal has a heat of combustion of 31.4 MJ/kg. In the United States the average coal-burnin...

Questions