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Scott
Scott, MIT Graduate
Category: Homework
Satisfied Customers: 3040
Experience:  MIT Graduate (Math, Programming, Science, and Music)
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Customer Question

Solve the following set of simultaneous equations.
2x +y-z = 10
4x-2z = 8
x+3z = -15
3. Solve the set of complex equations for A and B..
(4-j1) A +(3+j1)B = 200
(-3-j1)A-2 B = 40-j10
Express the result in both rectangular and polar forms. (Express the angle in radians)
4. The average current in a typical lightning thunderbolt is 20 kA and its typical duration is 0.1 s. The voltage between the clouds and the ground is 500 kV. Determine the total charge transmitted to the earth and the energy released.
5. An electroplating bath is used to plate silver uniformly onto objects such as kitchenware and plates. A current of 600 A flows for 20 minutes, and each coulomb transports 1.118 mg of silver. What is the weight of silver deposited in grams?
6. A walker’s cassette tape player uses four AA batteries in series to provide 6 V to the player circuit. The four alkaline battery cells store a total of 200 watt-seconds of energy. If the cassette player is drawing a constant 10 mA from the battery pack, how long will the cassette operate at normal power?
7. An electron beam is carrying 1015 electrons per second and is accelerated by passing through a voltage of 10 kV. The design engineer for this TV picture tube states that this circuit will result in a beam power of 16 W. Check this calculation and, if necessary, determine the required voltage to achieve 16 W.
(Note: An electron has a charge of –1.602x10-19 coulombs)
8. The Nelson River direct-current power line in Canada delivers 1.2 GW, at 900 kV, over a distance of 800 km. At the other end, at which the power is generated, the voltage is 950 kV. (a) Draw a circuit representation of the problem. (b) What is the efficiency of the line? That is, what is the power delivered divided by the power generated? (c) Where does the energy lost go? (d) How much energy (in kWh) is transmitted in a day if the conditions do not vary throughout the day?
9. The portable lighting equipment for a mine is located 100 meters from its dc supply source. The mine lights use a total of 5 kW and operate at 120 V dc. Determine the required cross-sectional area of the copper wires used to connect the mine lights if we require that the power lost in the copper wires be less than or equal to 5 percent of the power required by the mine lights.
10. An electric heater is connected to a 250-V source and absorbs 1000 W. Subsequently, this heater is connected to a constant 210-V source. What power does it absorb from the 210-V source? What is the resistance of the heater?
Submitted: 4 years ago.
Category: Homework
Expert:  Steve replied 4 years ago.

I can help you with the first 2 problems

Is that ok ?

Steve

Customer: replied 4 years ago.

alright fair enough what about the rest

Expert:  Steve replied 4 years ago.

I can´t do the rest, if you wan you can request me into a new post writing "For Steve"

And i do the first 2 questions for a lower cost and we can leave this post opened

maybe anther expert can do the rest here

Steve

Customer: replied 4 years ago.

so how long finish

Expert:  Steve replied 4 years ago.

I do not understand your last post

I can do the first 2 questions in another post

Steve

Customer: replied 4 years ago.

what do you mean by that


 

Expert:  Steve replied 4 years ago.

I can do only the first 2 questions

In this post i see that you have to pay around $70, is that ok ?

So you can open a new post with a lower cost

Steve

Customer: replied 4 years ago.

how to open a new post

Expert:  Steve replied 4 years ago.

I do not know exactly, how do you open this one ?

Steve

Customer: replied 4 years ago.

alright steve i would like to close this post and open another one so what will happen the 70 dollars on hold


 

Expert:  Steve replied 4 years ago.

Oh, sorry but i do not know exactly how it work (customer side)

Steve

Expert:  Steve replied 4 years ago.

Or you can leave his post opened for the rest

Steve

Customer: replied 4 years ago.

alright i will open a new post now and post a question and would like you to answer it and if i leave this post open they will not charge me 70 dollars even though you did not give me the answer

Expert:  Steve replied 4 years ago.

Ok, if you request me write "For Steve"

Steve

Customer: replied 4 years ago.

i would like to cancel this post steve please do not let it charge me

Expert:  Steve replied 4 years ago.

Ok,

post that here, write that you want to cancel this post

Customer: replied 4 years ago.

cancel this post

Expert:  Steve replied 4 years ago.
I will report it

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