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Natasha2012 [34]

3 years ago

8

A power plant burns coal at 830 K, and it exhaust to air at 288 K. If it runs at the Carnot efficiency, how much heat must it ex

haust into the air to produce 230,000 J of work?

2 answers:

statuscvo [17]3 years ago

8 0

Correct Answer:

122000 J

ElenaW [278]3 years ago

7 0

Answer:

122241.02 J

Explanation:

Work Done = 230000 J

$T_H=\text {High Temperature Reservoir}=830\ K\\T_L=\text {Low Temperature Reservoir}=288\ K\\\text{In case of Carnot Cycle}\\\text{Efficiency}=\eta\\\eta=1-\frac{T_L}{T_H}\\\Rightarrow \eta =1-\frac{288}{830}\\\Rightarrow \eta=0.65\\$

$\eta=\frac{\text{Work}}{\text{Heat}}\\\Rightarrow \eta=\frac{W}{Q_H}\\\\\Rightarrow 0.65=\frac{230000}{Q_H}\\\Rightarrow Q_H=\frac{230000}{0.65}\\\Rightarrow Q_H=352214.02$

$Q_L=Q_H-W\\\Rightarrow Q_L=352214.02-230000\\\Rightarrow Q_L=122241.02\ J$

∴Heat exhausted into the air to produce 230,000 J of work is 122241.02 Joule

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Can lamp that works on a 2.5 v work on a 1.12 v ?

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Answer:

Explanation:

Thinking about the logics it can but it may be dim because 1.12 is lower than 2,5v so this will mean u lamp may not work or may work very dimely due to the low voltage it is receiving.

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2 years ago

A wheel starts from rest and rotates with constant angular acceleration to reach an angular speed of 11.2 rad/s in 3.07 s. (a) f

Hitman42 [59]

(a) The angular acceleration of the wheel is given by
$\alpha = \frac{\omega_f - \omega_i }{t}$
where $\omega_i$ and $\omega_f$ are the initial and final angular speed of the wheel, and t the time.

In our problem, the initial angular speed is zero (the wheel starts from rest), so the angular acceleration is
$\alpha = \frac{(11.2 rad/s) - 0}{3.07 s} =3.65 rad/s^2$

(b) The wheel is moving by uniformly rotational accelerated motion, so the angle it covered after a time t is given by
$\theta (t) = \omega_i t + \frac{1}{2} \alpha t^2$
where $\omega_i = 0$ is the initial angular speed. So, the angle covered after a time t=3.07 s is
$\theta= \frac{1}{2} \alpha t^2 = \frac{1}{2}(3.65 rad/s^2)(3.07 s)^2 = 17.2 rad$

6 0

2 years ago

1. Identify which of the following will not increase the current induced in a wire loop moving through a magnetic field. a. incr

djyliett [7]

Answer:

Rotating the loop until it is perpendicular to the field

Explanation:

Current is induced in a conductor when there is a change in magnetic flux.

The strength of the induced current in a wire loop moving through a magnetic field can be increased or decreased by the following methods:

By increasing the strength of the magnetic field there will be increased in the induced current. If the strength of the magnetic field is decreased then there is a decrease in induced current.

By increasing the speed of the wire there will be increased in the induced current. When the speed of the wire is decreased then there is a decrease in induced current.

By increasing the number of turns of the coil the strength of the induced current can be increased. when there is less number of turns in coils then there is a decrease in induced current.

Rotating the loop until it is perpendicular to the field will not increase the current induced in a wire loop moving through a magnetic field.

Therefore, the option is (c) is correct.

4 0

2 years ago

A student pushes a 12.0 kg box with a horizontal force of 20 N. The friction force on the box is 9.0 N. Which of the following i

Hoochie [10]

The acceleration of the box is approximately $1 m/s^2$

Explanation:

According to Newton's second law of motion, the net force acting on the box is equal to the product between its mass and its acceleration:

$\sum F = ma$

where

$\sum F$ is the net force

m = 12.0 kg is the mass of the box

a is the acceleration

The net force can be written as

$\sum F = F_a - F_f$

where

$F_a = 20 N$ is the applied forward force

$F_f=9.0 N$ is the friction force

Combining the two equations,

$F_a-F_f=ma$

And solving for the acceleration,

$a=\frac{F_a-F_f}{m}=\frac{20-9}{12}=0.9 m/s^2\sim 1 m/s^2$

Learn more about Newton's second law:

brainly.com/question/3820012

#LearnwithBrainly

8 0

2 years ago

A larger object is made of two balls separated by a massless rigid rod that is 1.5 m long. The mass of the red ball at one end i

lions [1.4K]

Answer:

The speed of the 1 kg red ball 8.04 m/s .

Explanation:

Given :

Separation between rods , d = 1.5 m .

Mass of the red ball is 1 kg .

Mass of the orange ball is 5.7 kg .

Angular velocity , $\omega=1\ rev/s = 2\pi\ rad/s$ .

Now , distance of center of mass from red ball is :

$r =\dfrac{0\times 1+1.5\times 5.7}{1+5.7}\\\\r = 1.28\ m$

We know , speed is given by :

$v=\omega r\\\\v=2 \times \pi \times 1.28\\\\v=8.04\ m/s$

Hence , this is the required solution .

5 0

2 years ago