Engineering - December 2007

I have this electricity question in my exam:
"A manufacturing plant uses 2.1 MW of 220-V single phase power at a power factor of 0.8. Determine the apparent power and the effective, or rms, value of the current."
Getting the apparent power was simple, you just have to divide the true power by the power factor (which, in this case, gave you 2.625 MW), but I'm a bit confused as to the rms value.
To get the rms, you need the peak wave value (or the peak-to-peak value). I'm not sure how to get it. Could it be the amperage itself? Or maybe the voltage?

2007-12-20 11:00:54 · 4 answers · asked by Atomic Collision 2

2007-12-20 09:06:29 · 3 answers · asked by Anonymous

I'm in Grade 9 Science and all of this electricity stuff is getting on my nerves. I'm particularily confused with voltage. "The potential difference between two points on a curcuit in relation to blah blah blah..."; no, that crap just won't cut it. I don't know what the hell it means. My teacher just shows us the calculations for stuff and doesn't thoroughly explain anything. This is my worst unit yet. Can someone explain to me what these terms mean in a way that I can understand? I want to know a bit about what I'm working with here.

Also, how the heck do batteries work? My teacher goes on about these "cells" with a short line (-) and a long line (+) or something like that... but I have no idea what the heck she's talking about. Does she think we've learned about batteries already or something?

One more thing: Our teacher sais electrons flow out from the "negative terminal" on a battery. What I want to know is: WHY? What goes on inside a battery anyways?

2007-12-20 08:53:16 · 9 answers · asked by pb 2

Devise an inverse transformation that converts the U(0,1) into a beta with parameters alpha, beta. I need help on figuring out the formula which I will then put into excel.

Start with a random number from the uniform(0,1) distribution.

2007-12-20 05:59:37 · 3 answers · asked by Anonymous

At work we have AutoCAD. On my personal computer I want load one of the free, open software programs so that I could occasionally draw a sketch, or do a simple layout. Which software would you recommend?

2007-12-20 04:17:55 · 1 answers · asked by Tim C 7

just kidding, just testing the symbols!!!!!

2007-12-20 01:40:50 · 7 answers · asked by mattiadomain 1

A.) determined by the components that are external to the device
B.) High
C.) Low

2007-12-19 19:03:30 · 4 answers · asked by Anonymous

A forward biased E-B junction and a reverse biased C-B junction?

A reverse biased E-B junction and a reverse biased C-B junction?

A forward biased E-B junction and a forward biased C-B junction?

A reverse biased E-B junction and a forward biased C-B junction?

2007-12-19 18:52:09 · 1 answers · asked by random Q 2

2007-12-19 18:49:11 · 2 answers · asked by random Q 2

2007-12-19 18:47:03 · 1 answers · asked by random Q 2

There are two theories regarding this, Relativity of Einstain and Dynamic theory of garvity of Nikola Tesla. Dynamic theory of gravity basically negates the relativity with enough justifications and had actually been tested and proven physically by Tesla. On the other hand, relativity is proven by strong mathematical proofs. which one do you believe in? Tesla or Einstain?

2007-12-19 18:02:58 · 2 answers · asked by nimaomega 1

with a degree in aerospace engineering what kind of a job can i get in the air force or the army. and is it a good idea?

2007-12-19 15:40:57 · 6 answers · asked by Anonymous

2007-12-19 14:00:49 · 5 answers · asked by tweety_mek 1

we all know that for calculating area or perimeter of a circle, we should use pie. how the value of pie is determined and what is its importance

2007-12-19 13:02:47 · 21 answers · asked by roma 1

2007-12-19 12:22:16 · 3 answers · asked by Anonymous

I have a 12v/5ah sealed lead-acid battery wired to inverters, which are then wired to cold cathode tubes for a lighting effect under plexiglass on a table. My question is, what kind of on/off switch can I use to easily power the lights on and off without disconnecting the battery every time. Also, where in the line would it best be places?

Battery--->(split three ways)--->3 Inverters--->(split two ways each)--->lights (6 total). Make sense?

2007-12-19 11:31:59 · 2 answers · asked by MrTommyTCD 3

I would really like to know how to make a working lightsaber. I'm an amateur engineer that has been working on this for a while and I believe im too close to the project. Does anyone have good ideas on this subject?

2007-12-19 10:57:15 · 5 answers · asked by EL SEANO 1

2007-12-19 10:49:54 · 7 answers · asked by Anonymous

How I can made Excel Sheet Answer this equation mathematics ....
H(λ)= a0+a1(λ) +a2(λ)^2+a3(λ)^3
H(λ) =2.00 λ = 0.25
H(λ) =2.07 λ = 0.20
H(λ) =2.18 λ = 0.14
H(λ) =2.23 λ = 0.12
thanks for help

2007-12-19 10:34:37 · 3 answers · asked by muslim_heart_4ever 1

This is for a job with a company which I don't know their salary range. The job description looks that wrtien for somebody with my credential. I was with a company for a long time. Is it reasonable to ask for what I was making? This is a yong company with a lot of potentials.

2007-12-19 08:31:55 · 5 answers · asked by Sam S 1

I recently purchased a digital timer to connect my outdoor holiday lights. Reading the fine print on the back of the timer it says not to exceed electrical ratings.

Here are the electrical ratings:
125VAC, 8A resistive
125VAC, 600 Tungsten

I can find the voltage information for all of my holiday lights, but I do not how much voltage this timer can handle.

Can anybody provide me with basic information as to how much voltage this timer can handle? I want to make sure I do not overload the timer.

2007-12-19 07:33:34 · 5 answers · asked by Cooper 5

2007-12-19 07:32:29 · 8 answers · asked by drew 1

What is the total resistance of the three resistors.
a. 22 ohm
b. 15 ohm
c. 34 ohm
d. 127 ohm
e. 175 ohm

2007-12-19 07:29:50 · 5 answers · asked by Manh Cuong N 1

claims to cut heat bills by 50 percent want proof or amount of electric user in any given time period or kilowats usedif run continusley

2007-12-19 07:17:14 · 2 answers · asked by John W 1

Plz tell me in detail.... i really need help for final year project... and tell me how to program it

2007-12-19 07:11:38 · 7 answers · asked by Aleera V 2

Hi,
I need to hand in a 1st draft of my physics coursework tomorrow. I've made and tested a couple of circuits measuring the resistance of a thermistor at different temperatures. This is for the real-life situation of a drinks machine. The problem is I don't fully understand the purpose of a thermistor in a drinks machine. If it is to measure temperature why not just use a thermometer?
Any help would be greatly appreciated, apart from anything copied + pasted from wikipedia.

2007-12-19 07:05:04 · 5 answers · asked by Jethro 5

I need the results. I have e-value = [1,4] I need eigen-vector please?

2007-12-19 06:29:15 · 2 answers · asked by Ess 1

2007-12-19 06:28:47 · 7 answers · asked by STORMY K 3

Bucket wheel excavators are used extensively around europe to remove overburden and extract lignite for power stations.

The largest offer 240,000 tonnes per day production.

But just how efficient are they over a year.

What are the realistic yearly production rates.

I am curious as this is a lot for one machine to actually handle.

Is there any where I can check?

2007-12-19 05:38:32 · 1 answers · asked by Anonymous

2007-12-19 05:01:43 · 12 answers · asked by AirConditionedGypsy 1