Q:Please help, I'm stuck on this problem:An aluminum wire and a steel wire, each of length 4m, are hung from the ceiling. A 7 kg mass is suspended from the lower end of each wire. The aluminum wire has a diameter of 1.1 mm. What must be the diameter of the steel wire if it is to stretch the same distance as the aluminum wire, so that the two wires maintain equal lengths after masses are attached? Young's modulus for aluminum is .70 x 10^11 Pa and for steel it is 2.0 x 10^11 Pa.

With the usual symbols E= FL/eA, so F = EeA/L Call the aluminium wire '1' and the steel wire '2'. The tensions are the same (weight of 7kg) so: E?e?A?/L? = E?e?A?/L? Since the extensions and lengths are the same e?=e? and L? = L? so these cancel: E?A? = E?A? A?/A? = E?/E? Let the diameter of the aluminum wire be d? mm. Since the cross-sectional areas are proportional to the diametera squared: d??/d?? = E?/E? d? = 1.1 x √(0.70/2.0) = 0.65mm

Q:I have a 200 amp main breaker just below my meter, which is mounted on a pole. The neutral wire coming in is run to ground. From this box, I've run 2 cables (1/0) ~80 ft to another box with a 150 amp main breaker. This box is grounded to an 8ft ground rod. I am wondering whether this setup (no neutral wire from meter pole to building) would potentially allow a ground fault without tripping the 200 amp main. For example, if somebody dug into the line with a backhoe? Oh yeah, the cable is in a 3ft deep trench that will be covered. I have an abridged version of the NEC, but I haven't found this particular topic covered. Thanks.

what you did should be alright

Q:i bought a wiring kit off OKorder it was a bullz 4 gauge kit. and i am running a rockford 500.2 n its rated for 700+ watts. so do you think my cheaper wiring kit is affecting performance? should i go snag up some bigger power wire for more power to run through it or is tht not how it wokrs?

you should add a capacitor to your system. a 5 fared should be good. it is a reserve for when the bass hits. it's less stress on your alternator and battery. and you won't get the headlight dimming affect when you have it cranked up. ask your local car audio shop. you should be good with 4 gauge.

Q:I had recently closed up an outlet by taking the four wires and capping them off. Only to find out the two of the wires were for the ceiling fan power. I have a black and a white wire newer travelers to the ceiling fan, and two old cloth wires which look black. I do have an electrical tester and just want power for the fan, I will cover up the outlet. What wires go where ?

Wire nut the old hot wire to the black and the old neutral to the white. Connect the grounds together also. Find which is the old hot with your tester. Not with your finger. Good grief.

Q:I bought a single pole dimmer switch to install in my dining room and when I took the old switch out nothing looked right. There are two wires which were joined together by another single wire which was attached to the top screw. There was another single wire (I believe the ground wire) attached to the bottom screw. I disconnected the first two wires and attached them separately to the black wires on the dimmer and attached the ground wires together. It didn't work. I've tired several different times with no luck. I put the wires back the way they were and attached them to the old switch and they no longer work ether. Help! How can I fix this problem? The old wires appear to be a very thick copper covered in black plastic and cloth.....

How To Install A Dimmer

Q:what gauge wires should i use for my 12'' alpine typr r SWR-1242D?

4 guage amp kit This one is the best SoundQuest SQK0 1/0 Gauge Copper-Clad Aluminum Wiring Kit Technical Details * 1/0 Gauge Power and Grounding Wires * Remote Wire, Speaker wire, and RCA Signal Wires * Fuse Block and Fuse * Various crimp style connectors

Q:EL wire, or electroluminescent wire, is a wire which... well glows pretty colors lol. I want to buy some to make a costume, but I have some questions. I have a feeling that it will degrade over time, but how long will it take? Or do they start to degrade immeidately like glow sticks? What is it that causes them to glow, a chemical reaction or something else?

Electroluminescent okorder ) have wire that lasts far longer. You can expect the shelf life of these wires to be about 4-6 years. At that time, the wire just doesn't stop working, it slowly breaks down the phosphor particles, and the wire will get dimmer over time. The expected working life of EL Wire is about 4-6,000 hours which beats your average glow stick by about 5,992 hours...

Q:THERMOSTAT WIRING

What Sickwillie said.

Q:i need 175ft of 110 wire how much does it cost?

there is several kinds of 110 wire, and the price will vary according to the type and the day you buy it I would have to know what you were going to use it for to determine the approximate cost and the proper type. you could use 40 cents a foot as a guesstimate.

Q:Okay, I just started tearing into my partially finished basement of the home I bought last week. Some of the electrical wiring is interesting to say the least.I have a junction box in the basement. One wire connects directly to the panel, another out to an outlet, and the third goes up and out to half the house. All of this is 14/2 except the quot;thirdthat runs up and out. This is wired with 14/3 but the third wire isn't connected to anything. Should I be concerned considering every outlet in the house works?

Are you saying the 14/3 is being used as 14/2? Sometimes that is done because if at some later time you need the third line you have it. Or the electrician had extra wire and just used 14/3. 14/3 can be used for switched receptacle. a