Engineering - November 2007

Just curious

2007-11-10 13:50:11 · 8 answers · asked by Dude 4

Which will last longer - this rechargeable battery pack (the cells are in parallel): (http://www.radioshack.com/product/index.jsp?productId=2062121&cp=&sr=1&origkw=rc+battery+packs&kw=rc+battery+packs&parentPage=search)

or 6 energizer 1.2V, 2500mah rechargeable batteries in series?

The power supply will be routed to a 5V regulator, which, if it gets below 5.7V, will constantly reset (this is the "brownout protection; the supply is for powering a BS2e microcontroller, and other devides connected to a robot I am making. The brownout protector is internal in the microcontroller).

2007-11-10 11:37:12 · 3 answers · asked by Quackmaster7000 1

I currently am in the First Lego League Robotics Competition for my middle school, but soon I will be moving on to high school. My high school will not offer a robotics team, but I would like to continue with robotics as a "sport" as I complete my education. The prospect of battling robots interests me. Any help is appreciated.

2007-11-10 11:16:28 · 1 answers · asked by house.md_rules 2

I also need a schematic for this design?

2007-11-10 10:42:59 · 1 answers · asked by Anonymous

dont shout at me if you know who my science teacher is or what project i am talking about...

anyway i have a project due in three months and i really need help getting started. can anyone show me a website or the name if a book which can help me with my project? we have to build a hoist that can lift a mass of 2 kilograms 10 cm up and 10 cm to the side...with one switch..but we have no idea how to build it or where to put the switch or the motor or anything at all...

PLEASE HELP US!!!!!!!!!!!!!!!!!!!! =]


AND I REPEAT: DO NOT CUSS AT ME or any mean comments please?

2007-11-10 10:03:43 · 6 answers · asked by *~Simplymyself~* 3

How do i calculate the current flow in a domestic mains circuit?
I remember the ohms law triangle from school, V I R and i know there is one for power (watts) calculations, i researched this online although i have since forgot how that one is layed out ? In any case i thought it was W/V=I, so for my electrical item this would be 600/240=2.5 amps However on the item itself there are 2 ratings- 3 amps and 6.2 amps clearly 3 amps refers to my above calculation plus a safety margin, where does 6.2 amps arise from- there is reference to the cos value, I vaguely know about including the cos calculation but do not know how it works or when it applies? I live in the UK in a standard residential property with a normal mains supply.......

2007-11-10 09:31:30 · 9 answers · asked by nurnord 7

2007-11-10 09:17:27 · 7 answers · asked by greenhaus2002 1

If I'm building a DC motor with pemanent magnet stator, is it best to use large gauge wire for a low resistance, high ampage coil or use thinner wire to get a higher resistance and therefore require higher voltages for the same output power?

The intention is to power a vehicle with the finished motor, so a wide speed range and low speed torque are important.

2007-11-10 09:15:15 · 7 answers · asked by Doom 2

2007-11-10 07:14:03 · 2 answers · asked by Shary 6

i also noticed that some moblies have a powerful viberation.. plz can any body tell how it works, wats that thing which makes the mobile to get shaked

2007-11-10 06:54:10 · 4 answers · asked by amr 2

can the carosene be blocked from flowing into the engine so the wind can put out the fire?

2007-11-10 06:19:53 · 5 answers · asked by snippi f 2

Help! Thanks!

2007-11-10 05:21:00 · 3 answers · asked by Anonymous

If I wish to use the eigenvalue or real symmetric matrix as term project for numerical analysis for senior undergraduate, which size of the matrix should I restrict the original matrix? In the sense that it will not be too hard nor too easy. Also should I restrict the original matrix to be sparse. The required implementation language will be C++.

2007-11-10 05:03:39 · 1 answers · asked by ivision 1

At work I do stress analysis on launch vehicles. Our loads and dynamics group gives us loads (in pounds) called "Peq" or P_equivalent at various "stations" or vertical coordinates of the rocket. Most rockets, including ours, consist of a stack of lightweight hollow cylindrical structures all bolted together. The loads in these structures increase as we go down the rocket (obviously because the lower you go the more weight the structures carry along with the aero loads and pressures. My question is, what do they mean by Peq? How do they calculate these loads? I've always been curious. The loads group just keeps feeding us these numbers we plug into our models but have no idea where they come from. If anyone who does the same type of work as me could respond, that would be awesome. Thanks!

2007-11-10 04:26:37 · 2 answers · asked by Dr S 4

I need the precision not the accuracy. Accuracy should be around 1 to 2 degrees C.

2007-11-10 04:10:02 · 3 answers · asked by worriedguy 1

2007-11-10 03:45:45 · 6 answers · asked by LA 1

I love electronics, but I am considering studying Electrical Engineering instead of the technology. I like working with my hands and doing projects, but at the sametime I also want to be the guy who designs the technology. I need some advice with people with industry related experience.

2007-11-10 03:41:03 · 2 answers · asked by Alex Borges 1

i have a machine that requires 440 3 phase power, i have 220 all over the place. can a 440 primary 220 secondary be used in reverse to step up from 220 to 440? 75 kva transformers are easy to come by, but i dont know if they can be used this way.

2007-11-10 02:44:44 · 9 answers · asked by tulmkr 1

A 20 g rifle bullet traveling 205 m/s buries itself in a 3.0 kg pendulum hanging on a 2.9 m long strng, which makes the pendulum swing upward in an arc.
Determine the vertical and horizontal compnents of the pendulum's dispalcement,
vertical m
horizontal m

2007-11-10 01:47:52 · 1 answers · asked by cindy d 4

2007-11-09 23:56:17 · 5 answers · asked by cHARLES W 1

if the current waveform is i=10cos(314t-60degrees)
and the voltage waveform v=50sin(314t-45degrees)
then the phase difference is said to be 75 degrees but how do u get this?
the answer says 30degrees - (-45degrees)

2007-11-09 23:02:10 · 2 answers · asked by Nrt A 1

2007-11-09 18:08:39 · 9 answers · asked by risay l 1

The resistivity of copper is 17.24 nanohm meters.
can some one show me all the workings of this question including the formula used.

2007-11-09 16:49:25 · 2 answers · asked by Chris B 1

2007-11-09 14:46:24 · 3 answers · asked by Anonymous

2007-11-09 13:24:26 · 4 answers · asked by Zzz 1

This is something I've always wondered about but never bothered asking. Say you go to a home/car audio store to look at amplifiers. You have 2 amps, both made by the same company, both almost the same model, both of the same quality parts -- the only difference is the price and the wattage.

What exactly makes higher wattage amplifiers cost more money than lower wattage amplifiers? Do they just price higher wattage amps higher to make more money off of enthusiasts or are there technical reasons behind this?

I don't know too terribly much about electronics, but something seems a little fishy here. As far as I know, wattage is just determined by how much power is outputted, which to me is almost directly related to the power input, which is just amplified by other circuitry.

It just doesn't make sense to me why this would constitute a higher price.

Anyone know about this sort of stuff?

I hope I categorized this question right. Electrical engineering is what I was really after

2007-11-09 12:29:58 · 4 answers · asked by Adam 2

Hey Guys, What's the best choice
of flux cored welding wire which
is also low hydrogen. Using shielding gas and no gas?

2007-11-09 11:42:31 · 2 answers · asked by George G 1

Find the x- and y-coordinates of the center of gravity of a 4.00 ft by 8.00 ft uniform sheet of plywood with the upper right quadrant removed. The dimensions of the cutout are a = 4.90 ft and b = 2.10 ft.
x =____ ft
y = ____ft

2007-11-09 10:14:18 · 2 answers · asked by ? 1

2007-11-09 09:52:26 · 9 answers · asked by Anonymous

2007-11-09 05:31:46 · 1 answers · asked by Anonymous