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2 years ago

All machines are less than 100% efficient. True False

Physics

2 answers:

san4es73 [151]2 years ago

6 0

Answer:

false

Explanation:

because no machines have 100% efficient

Ugo [173]2 years ago

5 0

Answer:

false

Explanation:

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Neon is compressed from 100 kPa and 24°C to 500 kPa in an isothermal compressor. Determine the change in the specific volume and

trasher [3.6K]

Answer:

ΔV = -0.97 m³/ kg

ΔH = 0 kJ/ kg

Explanation:

To determine the change in the specific volume we need to use the ideal gas law:

$PV = RT$

where P: pressure of the gas V: volume of the gas, R: ideal gas constant= 0.4119 kJ/kg.K = 0.4119 kPa.m³/kg.K and T: temperature of the gas.

The V₁, at a compressed pressure is:

$V_{1}= \frac {RT}{P_{1}}$

$V_{1}= \frac {0.4119 \frac{kPa\cdot m^{3}}{kg\cdot K} \cdot (24 + 273 K)}{100 kPa}$

$V_{1}= 1.22 \frac{m^{3}}{kg}$

Similarly, the V₂ is:

$V_{2}= \frac {RT}{P_{2}}$

$V_{2}= \frac {0.4119 \frac{kPa\cdot m^{3}}{kg\cdot K} \cdot (24 + 273 K)}{500 kPa}$

$V_{2}= 0.25 \frac{m^{3}}{kg}$

Now, the change in the specific volume because the compressor is:

$V_{2} - V_{1} = 0.25 - 1.22 \frac{m^{3}}{kg}$

$V_{2} - V_{1} = -0.97 \frac{m^{3}}{kg}$

Finally, to calculate the change in the specific enthalpy, we need to remember that neon is an ideal gas and that is an isothermal process:

$\Delta H = C_{p} \cdot \Delta T$

$\Delta H = 1.0299 \frac{kJ}{kg \cdot K} \cdot 0$

$\Delta H = 0 \frac{kJ}{kg}$

Have a nice day!

7 0

4 years ago

Explain why liquids flow but solids do not.

goldfiish [28.3K]

Because they have no dignified shape they take on the shape of whate ever container they are in and when you pour in out it can't really take any shape except tho lay flat on the table. and solids do not flow because they have a dignified shape. hope it helps!

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3 years ago

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Please select the word from the list that best fits the definition.

poizon [28]

The true answer is the choice B.Anton van Leeuwenhoek
this one was a Dutch biologist, inventor and physicist (1632, 1723). he has discoverd the moving objects from pond water undr his microscope, the animalcules.

4 0

3 years ago

You jump off a truck and accelerate toward the surface of the Earth. Does the Earth accelerate toward you?

Triss [41]

When we jump from the truck and accelerate towards the earth surface, the earth also accelerates towards us but it's acceleration is very negligible.

To find the answer, we need to know about the acceleration of earth due to the gravitational attraction.

<h3>What's the gravitational force between the earth and a person?</h3>

Gravitational attraction force is GMm/r² between the earth and a person.
M= mass of the earth

m= mass of the person

r= separation between them.

<h3>What's the acceleration of the earth towards the person when he jumps from a truck?</h3>

According to Newton's second law, Force = M×acceleration
Acceleration= Force / M
Here, Force = GMm/r²,

so acceleration of earth= Gm/r²

As this acceleration is very small, so we can't notice it.

Thus, we can conclude that the earth also accelerates towards us.

Learn more about the gravitational force here:

brainly.com/question/72250

#SPJ4

7 0

2 years ago

Why evaporation are called surface phenomenon?

Eva8 [605]

The water formed on the surface of the water evaporation loss (evaporation), consisting of plant transpiration water loss (transpiration) is called. Soil near the plant and the resulting water loss is called by evapotranspiration.

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4 years ago

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All machines are less than 100% efficient. True False​

All machines are less than 100% efficient. True False