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3 years ago

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A 4 kW vacuum cleaner is powered by an electric motor whose efficiency is 90%. (Note that the electric motor delivers 4 W of net

mechanical power to the fan of the cleaner). What is rate at which this vacuum cleaner supplies energy to the room when running

1 answer:

RoseWind [281]3 years ago

3 0

Answer: $3.6\ kW$

Explanation:

Given

Power Supplied $[tex]P_{input}=4\ kW$ [/tex]

Efficiency of the motor $\neta =90\%$

and $\neta =\dfrac{\text{Power output}}{\text{Power input}}$

$\Rightarrow 0.9=\dfrac{P_{out}}{4}$

$\Rightarrow P=0.9\times 4$

$\Rightarrow P=3.6\ kW$

So, vacuum cleaner delivers a power of $3.6\ kW$

You might be interested in

A voltage amplifier needs a high input resistance and a low output resistance. Select one: True False

cupoosta [38]

Answer:

Explanation:

In electric circuit , the potential difference is always developed across the resistance .

Now is we are to amplify the voltage , that means low input voltage is converted into high voltage output .

Therefore we require low resistance at input for low voltage and high out put resistance for high output

Thus the statement given is wrong .

6 0

3 years ago

Choose all the answers that apply.

slava [35]

<h2>So, the correct answers are:</h2>

Travels in longitudinal waves

Travels most slowly through a gas

Speeds up when temperature is increased

Is caused by vibration

Explanation for correct answers:

Yes, it does travel in longitudinal waves

Yes, sounds weird, but travels faster in the water

Yes, does speed up when temperature is increased

And yes, Is caused by vibration.

<h2>Wrong answer is:</h2>

Can travel through a vacuum

Explanation for wrong answer:

actually, in space, there is NO sound, because there are no particals for the sound to vibrate with, there's just empty SPACE.

5 0

3 years ago

A circular coil has a 8.79 cm radius and consists of 42.0 closely wound turns of wire. An externally produced magnetic field of

OverLord2011 [107]

Answer: The magnetic flux is 3.4 × 10^-3 Wb

Explanation: Please see the attachments below

8 0

3 years ago

A composite load consists of three loads connected in parallel. One draws 100 W at a PF of 0.92 lagging, another takes 250 W at

fenix001 [56]

Answer:

a) $I_{RMS} = 4.79 A$

b) $PF = 0.908$

Explanation:

Get the reactive powers for each of the loads:

Reactive power = Real Power * tanθ

For load 1

Active power, P₁ = 100 W

Power factor, $cos \theta_{1} = 0.92$

$\theta_{1} = cos^{-1} 0.92\\\theta_{1} = 23.074$

$Q_{1}= P_{1} tan \theta_{1} \\Q_{1}= 100tan 23.074\\Q_{1}= 42.60 W$

For load 2

Active power, P₂ = 250 W

Power factor, $cos \theta_{2} = 0.8$

$\theta_{2} = cos^{-1} 0.8\\\theta_{2} = 36.87$

$Q_{2}= P_{1} tan \theta_{2} \\Q_{2}= 250tan 36.87\\Q_{2}= 187.5 W$

For load 3

Active power, P₃ = 250 W

Power factor, $cos \theta_{3} = 1$

$\theta_{3} = cos^{-1} 1\\\theta_{3} =0$

$Q_{2}= P_{1} tan \theta_{3} \\Q_{3}= 150tan 0\\Q_{3}= 0 W$

Calculate the total reactive power, $Q_{net} = 42.6 + 187.5 + 0$

$Q_{net} = 230.1 W$

Calculate the total active power, $P_{net} = 100 + 250 + 150 = 500 W$

$S_{net} = P_{net} + Q_{net} \\S_{net} = 500 + j230.1$

$P_{net} = IVcos \theta_{net}$

$\theta_{net} = tan^{-1} \frac{230.1}{500} \\\theta_{net} = 24.712$

V = 115 $V_{rms}$

$500 = I_{RMS} * 115 cos 24.712\\I_{RMS} = 500/104.47\\ I_{RMS} = 4.79 A$

b) Power factor of the composite load is $cos\theta_{net}$

$\theta_{net} = 24.712\\PF = cos 24.712\\PF = 0.908$

4 0

3 years ago

On June 21, the sun never sets at John's location. Based on this, it can be concluded that John lives:

Lesechka [4]

It can be concluded that John lives at the Arctic Circle.

<h3></h3><h3>Why sun don't sets at arctic circle?</h3>

The North Pole is inclined toward our star throughout the summer because of the slanted axis of the earth's rotation with respect to the sun. Because of this, the sun never sets over the Arctic Circle for a few weeks.

Norway. Norway, which is located in the Arctic Circle, is known as the Land of the Midnight Sun because there the sun never sets from May until late July. This implies that the sun doesn't set for around 76 days.

to learn more about arctic circle go to -

brainly.com/question/10306896

#SPJ4

4 0

2 years ago