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2 years ago

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A coal - fired power station produces 100MJ of electrical energy when it is supplied with 400MJ of energy from its fuel. The eff

iciency of the power station is ______

1 answer:

Alexus [3.1K]2 years ago

8 0

Answer:

100 divide by 400 times 100 percent

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Unlike velocity, speed is scalar, which means it is described by ______<br> only.

natali 33 [55]

Hi there,

Unlike velocity,speed is scalar,which means it is described by MAGNITUDE only.

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3 years ago

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Which transition represents a time when water molecules are moving closer together?

oee [108]

The best transition between the four options presented to represent a time when water molecules are moving closer together would be A. Frost forms on a window pane.

The closest distance that the water molecules can do is when the water is in the state of being solid. It is known that the solid state of matter has the closest distance from molecule to molecule that when a molecule tries to move, the others move as well creating a vibration and thus producing heat in the process. When they are in a liquid state, they are quite far from each other. In a gas state, they really are far from each. This explains the difference in their characteristics.

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3 years ago

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In a hydroelectric power plant, water flows from an elevation of 400 ft to a turbine, where electric power is generated. For an

VashaNatasha [74]

Answer:

$V=3.475ft^3/s=3.48ft^3/s$

Explanation:

We have here values from SI and English Units. I will convert the units to English Units.

We hace for the power P,

$P= 100kW \rightarrow 100kW*(\frac{737.56ft.lbf/s}{1kW})$

$P= 73.7*10^{3}ft.lbf/s$

we have other values such $h=400ft$ and $\gamma= 62.42lb/ft^3$ (specific weight of the water), and 0.85 for \eta

We need to figure the flow rate of the water (V) out, that is,

$V=\frac{P}{\gamma h \eta_0}$

Where $\eta_0$ is the turbine efficiency, at which is,

$\eta_0 = \frac{P}{\gamma Vh}$

Replacing,

$V=\frac{73.7*10^{3}}{62.42*400*0.85}$

$V=3.475ft^3/s$

With this value (the target of this question) we can also calculate the mass flow rate of the waters,

through the density and the flow rate,

$m=\rho V\\m= 3.475*1.94 \\m=6.7415 slugs/s$

converting the slugs to lbm, 1slug = 32.174lbm, we have that the mass flow rate of the water is,

$m= 217lbm/s$

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3 years ago

6.Convert 22 °C to K. (°C = K - 273)

DIA [1.3K]

Answer:

295

Explanation:

if C = k - 273

k = C + 273

substitute 22 for C

K = 22 + 273

k = 295

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3 years ago

A block of mass 3. 0 kg is hung from a spring, causing it to stretch 12 cm at equilibrium, as shown above. The 3. 0 kg block is

QveST [7]

Answer: 32 cm

Explanation:

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2 years ago