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Varvara68 [4.7K]
3 years ago
5

A heat engine receives 7000 j of heat and loses 3000 j in each cycle. what is the efficiency of this engine?

Physics
1 answer:
Nonamiya [84]3 years ago
4 0

Answer: 57.1 %

Explanation:

The efficiency of the engine is given by:

\eta=\frac{Q_{used}}{Q_{in}}

where the numerator corresponds to the heat used by the engine, while the denominator corresponds to the heat in input to the engine.

In this problem, the heat in input is

Q_{in}=7000 J

while the heat used is

Q_{used}=7000 J-3000 J=4000 J

So, the efficiency is

\eta=\frac{4000 J}{7000 J}=0.571=57.1\%


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What are the different isotopes
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Answer:

Isotopes can both be the same element but have a different number of electrons

Explanation: not sure if more was supposed to be there, but i tried

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3 years ago
A 50 W light bulb is plugged into a standard
wolverine [178]

Answer:

$1.26

Explanation:

Power =energy/ time

energy =powerxtime

energy =50x31x24=37200

=37.2kwh

1kwh =3.39

37.2kwh=3.39x37.2=126.108cent

=$1.26

8 0
2 years ago
A person jogs for 4.0 km in 32 mins,then 2.0km in 22mins,and finallu 1.0 km in 16 mins.whqt is the joggers average speed in km p
blondinia [14]

Average speed = (total distance covered) / (time to cover the distance)

total distance covered = (4km + 2km + 1km) = 7 km

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5 0
3 years ago
A rock is lifted by a machine to a height of 10m. If it has a mass of 22 kilograms
zmey [24]

Answer:

2156J

Explanation:

Given parameters:

Height of lift  = 10m

Mass  = 22kg

Unknown:

Work done by the machine  = ?

Solution:

Work done is the force applied to move a body through a certain distance.

So;

        Work done  = Force x distance

Here;

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5 0
3 years ago
The rectangular plates in a parallel-plate capacitor are 0.063 m x 5.4 m. A distance of 3.5 x 10^-5m separate the plates. The pl
Aleks04 [339]

The capacitance of the capacitor is 1.8\cdot 10^{-9}F

Explanation:

The capacitance of a parallel-plate capacitor is given by the equation

C=\frac{k\epsilon_0 A}{d}

where

k is the dielectric constant of the medium

\epsilon_0 = 8.85\cdot 10^{-12} F/m is the vacuum permittivity

A is the area of the plates

d is the separation between the plates

For the capacitor in this problem, we have:

k = 2.1 is the dielectric constant

d=3.5\cdot 10^{-5}m is the separation between the plates

A=0.063m \cdot 0.054m = 0.0034 m^2 (I assumed that 5.4 m is a typo, since it is not a realistic size for the side of the plate)

Therefore, the capacitance of the  capacitor is

C=\frac{(2.1)(8.85\cdot 10^{-12})(0.0034)}{3.5\cdot 10^{-5}}=1.8\cdot 10^{-9}F

Learn more about capacitors:

brainly.com/question/10427437

brainly.com/question/8892837

brainly.com/question/9617400

#LearnwithBrainly

5 0
3 years ago
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