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3 years ago

10

Power input formulae

2 answers:

Darina [25.2K]3 years ago

4 0

Power = work / time

this means power = force * displacement / time

in electricity this equates to P = IV

When in doubt with this sort of stuff type "power equation" into google images it usually throws out a few gems :)

djyliett [7]3 years ago

3 0

Power = (work done) / (time to do the work)

Power = (energy moved) / (time to move the energy)

Power = (voltage) x (current)

Power = (voltage)² / (resistance)

Power = (current)² x (resistance)

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An engine draws energy from a hot reservoir with a temperature of 1250 K and exhausts energy into a cold reservoir with a temper

bixtya [17]

Answer:

a. $P=18.61\ W$

b. $\eta_c=0.6976=69.76\%$

c. $\eta=0.4718=47.18\%$

Explanation:

Given:

temperature of the hotter reservoir, $T_H=1250\ K$

temperature of the colder reservoir, $T_C=378\ K$

heat absorbed by the engine, $Q_H=1.42\times 10^{5}\ J$

heat rejected to the cold reservoir, $Q_L=7.5\times 10^4\ J$

time duration of the energy transfer, $t=1\ hr=3600\ s$

<u>Now the work done by the engine:</u>

Using energy conservation,

$W=Q_H-Q_L$

$W=14.2\times 10^4-7.5\times 10^4$

$W=6.7\times 10^4\ J$

a.

<u>Hence the power output:</u>

$P=\frac{W}{t}$

$P=\frac{6.7\times 10^4}{3600}$

$P=18.61\ W$

b.

$\eta_c=1-\frac{T_L}{T_H}$

$\eta_c=1-\frac{378}{1250}$

$\eta_c=0.6976=69.76\%$

c.

now actual efficiency:

$\eta=\frac{W}{Q_H}$

$\eta=\frac{6.7\times 10^4}{1.42\times 10^{5}}$

$\eta=0.4718=47.18\%$

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Which of the following are true statements about electronegativity?Check all that apply.A. Electronegativity increases as you mo

stiks02 [169]

I Know it is b i got my dad to help me with that test

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3 years ago

Read 2 more answers

The place you get your hair cut has two nearly parallel mirrors 6.5 m apart. As you sit in the chair, your head is 2.0 m from th

ASHA 777 [7]

Answer:

13 m

Explanation:

It is given that :

I got a haircut sitting at a place having two parallel mirrors at a distance = 6.5 m apart

My head is at a distance of 2 m from the nearer mirror.

Now the light from the back of my head must go to (6.5 - 2) = 4.5 m to the back mirror.

Then it must go to 6.5 m to the front mirror and 2 m from the front mirror to my eyes.

So in order to see the back of my head, it will be = 6.5 + 2 + 4.5 = 13 m away.

4 0

3 years ago

Calculate the power rating of a home appliance (in kilowatts) that uses 5.1 amps of current when plugged into a 120 Volt outlet.

Mrrafil [7]

Answer:0.612 kilowatts

Explanation:

Current=5.1 amperes

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Power=current x voltage

Power=5.1 x 120

Power=612

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power=612/1000 kilowatts

Power=0.612 kilowatts

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4 years ago

Relative to the ground, what is the gravitational potential energy of 68 kg

Kisachek [45]

Answer:

Explanation:

p.E=mgh

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2 years ago