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3 years ago

Power is calculated by multiplying voltage by

1 answer:

5 0

If you're calculating the power of an athlete who is lifting weights,
or the power of a windmill that is pumping water from a well, or
the power of two horses turning millstones, then those electrical
units won't help at all.

But if you happen to be calculating the power delivered to an
electrical circuit or dissipated by an electrical device, then you
can use ...

(voltage) times (current)
or
(voltage)² divided by (resistance)
or
(current)² times (resistance) .

The choice just depends on which quantities you know
or can easily measure.

You might be interested in

Velocity is described by __ and time

klasskru [66]

Answer:

direction and time

Explanation:

4 0

4 years ago

Steam flows steadily through an adiabatic turbine. The inlet conditions of the steam are 4 MPa, 500◦C, and 80 m/s, and the exit

Cerrena [4.2K]

Answer:

a) ΔEC=-23.4kW

b)W=12106.2kW

c) $A=0.01297m^2$

Explanation:

The kinetic energy is defined as:

$\frac{m*vel^2}{2}$ (vel is the velocity, to differentiate with v, specific volume).

The kinetic energy change will be: Δ ( $\frac{mvel^2}{2}$ )= $\frac{m*vel_2^2}{2}-\frac{m*vel_1^2}{2}$

Δ ( $\frac{mvel^2}{2}$ )= $\frac{m}{2}*(vel_2^2-vel_1^2)$

Where 1 and 2 subscripts mean initial and final state respectively.

Δ( $\frac{mvel^2}{2}$ )= $\frac{12\frac{kg}{s}}{2}*(50^2-80^2)\frac{m^2}{s^2}=-23400W=-23.4kW$

This amount is negative because the steam is losing that energy.

Consider the energy balance, with a neglective height difference: The energy that enters to the turbine (which is in the steam) is the same that goes out (which is in the steam and in the work done).

$H_1+\frac{m*vel_1^2}{2}=H_2+\frac{m*vel_2^2}{2}+W\\W=m*(h_1-h_2)+\frac{m}{2} *(vel_1^2-vel_2^2)$

We already know the last quantity: $\frac{m}{2} *(vel_1^2-vel_2^2)$ = $-$ Δ ( $\frac{mvel^2}{2}$ )=23400W

For the steam enthalpies, review the steam tables (I attach the ones that I used); according to that, $h_1=h(T=500C,P=4MPa)=3445.3\frac{kJ}{kg}$

The exit state is a liquid-vapor mixture, so its enthalpy is:

$h_2=h_f+xh_{fg}=289.23+0.92*2366.1=2483.4\frac{kJ}{kg}$

Finally, the work can be obtained:

$W=12\frac{kg}{s}*(3445.3-2438.4)\frac{kJ}{kg} +23.400kW)=12106.2kW$

C) For the area, consider the equation of mass flow:

$m=p*vel*A$ where $p$ is the density, and A the area. The density is the inverse of the specific volume, so $m=\frac{vel*A}{v}$

The specific volume of the inlet steam can be read also from the steam tables, and its value is: $0.08643\frac{m^3}{kg}$ , so:

$A=\frac{m*v}{vel}=\frac{12\frac{kg}{s}*0.08643\frac{m^3}{kg}}{80\frac{m}{s}}=0.01297m^2$

Download pdf

7 0

3 years ago

What is the length of the color attribute?

astraxan [27]

The length of the colour attribute is 6 characters.

<h3>What is a colour attribute?</h3>

Each colour has a distinct look based on three essential characteristics: hue, chroma (saturation), and value (lightness). It's critical to use all three of these properties when describing colour to appropriately identify it and distinguish it from others.

<h3>What is the use of colour attributes?</h3>

The HTML <font> color Attribute specifies the text color within the font element. Values of Attributes: colour name: It uses the colour name to set the text colour.

It should be noticed that colours are represented by the hex triplet.

Learn more about colour attributes here:

brainly.com/question/18071208

#SPJ4

6 0

2 years ago

In the formula vy = ayt, what is the value of ay for an object in projectile motion?

Sergeu [11.5K]

–9.8 m/s<span>2

Just took it and got it right!</span>

8 0

3 years ago

Read 2 more answers

A 3 kg rubber block is resting on wet concrete. The coefficient of static friction is 0.3. What is the minimum force that must b

mrs_skeptik [129]

Answer:

You would have to find the friction force of the rubber block which would be found with the equation of Normal force (mass*gravity) times cooeficient of friction which would give 8.82 N for the amount of friction and because you need more force than 8.82 N (assuming gravity is 9.8)

8 0

3 years ago