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3 years ago

Visual perception can be improved through perceptual skills development. False True

Engineering

1 answer:

bogdanovich [222]3 years ago

4 0

Answer:

It's true

Explanation:

I took the quiz a few days ago and got it right!

Hope this helps:)

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The basic concept of feedback control is that an error must exist before some corrective action can be made?

weqwewe [10]

Answer:

The correct answer is True.

Explanation:

The feedback control system implies that to make a feedback, there must first be an error, otherwise there will be nothing to correct.

This system works so that there is an output that is controlled through a signal.

This signal will be feedback and it will signal an error which will be detected by a controller that will allow entry into the system.

In basic words, this system processes signals, samples them in the form of an output, and re-enters them feedback to detect the error signal.

7 0

3 years ago

The water level in a tank is 20 m above the ground. A hose is connected to the bottom of the tank, and the nozzle at the end of

weeeeeb [17]

Answer:

$P_{pump}= 68600Pa$

Explanation:

We understand that the sum of the pressures in the tank and the pump is equal to that of the Nozzle,

In this way,

$P_{tank} + P_{pump} = P_{nozzle}$

For the pressure we also know that it is given by

$P=\rho gh$

$\rho gh_1 + P_{pump} = \rho gh_2$

So,

$P_{pump} = \rho g(h2 - h1)$

$P_{pump}= 1000*9.8(27-20)$

$P_{pump}= 68600Pa$

7 0

3 years ago

A household refrigerator that has a power input of 450 W and a COP of 1.5 is to cool five large watermelons, 10 kg each, to 8°C.

Andreyy89

Answer:

6222.22 sec

Explanation:

Given data the power input to the refrigerator is 450 W

The COP of refrigerator is 1.5

Temperature $T_1=8^{\circ}C$

$T_2=28^{\circ}C$

mass of watermelon =10 kg

specific heat =4.2 KJ/kg°C

The amount of heat removed from 5 watermelon

$Q=mc_pdt=5\times 10\times 4.2\times (28-8)=4200 KJ$

We know that $COP=\frac{Q_1}{W}$

$1.5=\frac{Q_1}{450}$

$Q_1=675$ W=0.675 KW

so time required to cool the watermelon is

$t=\frac{Q_1}{Q_2}=\frac{4200}{0.675}=6222.22 sec$

4 0

3 years ago

Suppose that the cost of electrical energy is $0.15 per kilowatt hour and that your electrical bill for 30 days is $80. Assume t

mr_godi [17]

Answer:

a) 740 W b) 6.2 A c) 8.1%

Explanation:

We need first to get the total energy spent during the 30 days, that can be calculated as follows:

1 month = 30 days = 720 hr

If the total cost amounts $80 (for 720 hr), and the cost per kwh is 0.15, we have:

80 $/mo = 0.15 $/Kwh*x Kwh/mo

Solving for the total energy spent in the month:

$x (kwh/mo) = \frac{80}{0.15} = 533.3 kwh$

Assuming that the power delivered is constant over the entire 30 days, as power is the rate of change of energy, we can find the power as follows:

$P = \frac{E}{t} = \frac{533.3 kWh}{720 h} = 0.74 kW = 740 W$

b) If the power is supplied by a voltage of 120 V, we can find the current I as follows:

$I =\frac{P}{V} =\frac{740W}{120V} = 6.2A$

c) If part of the electrical load is a 60-W light, we can substract this power from the one we have just found, as follows:

P = 740 W - 60 W = 680 W

The new value of the energy spent during the entire month will be as follows:

E = 0.68 kW*24(hr/day)*30(days/mo) = 490 kWh/mo

The reduction in percentage regarding the total energy spent can be calculated as follows:

ΔE = $\frac{533.3-490}{533.3} = 0.081*100= 8.1%$

⇒ ΔE(%) = 8.1%

$%(E) =\frac{533.3-490}{533.3} = 0.081 * 100 = 8.1%$

4 0

4 years ago

Briggs & Stratton engines feature both a pressure lubrication and a pressure filtration system. Which statement is true?

Andreyy89

Answer would be Letter B

7 0

3 years ago