Science & Mathematics - 30 August 2007

5. A step-down transformer rated at 500 W can supply 110V 60Hz (secondary) from a 220V 60Hz (primary) line voltage. If the secondary is connected to a 2.5V DC supply, what voltage can be expected at the primary side?

2007-08-30 02:05:15 · 5 answers · asked by andrew 1 in Engineering

1. How much power will a 740W electric flat iron rated at 220V 60 Hz consume if 220V DC is used instead? Assume here that the iron is purely resistive and that the resistance does not change with a change in voltage.

2007-08-30 02:04:17 · 2 answers · asked by andrew 1 in Engineering

Determine the resulting % power savings of a typical household in the Philippines if the line voltage drops from 220V to 200V (rms). Assume that 2.5 kW is used by the household for an average of 12.7 hours per 24-hour day and that the equivalent total resistance of the household fixtures and appliances do not change with a decrease in line voltage.

2007-08-30 02:03:07 · 4 answers · asked by andrew 1 in Engineering

Has anyone heard of something called the "deep sound channel". The way I understand it it's a deep layer in the ocean where the pressure is so great that it confines sound waves and can be used to send messages to other areas of the oceans and is used by the Navy for long distance communications.

2007-08-30 02:01:57 · 3 answers · asked by ericbryce2 7 in Earth Sciences & Geology

What is the link within it that explains how the different sexes formed, and why they formed from being either both sexes, or from a-sexual to having to sexes?

2007-08-30 02:01:49 · 2 answers · asked by Anonymous in Biology

Conspiracy theory’s aside: Why have I never seen a photo taken from earth of the US Flag planted on the moon or the ‘jeep’ that was left behind. We have telescopes that capture images from distant planets, but why hasn’t anyone taken pictures of the objects left on the moon?

Conspiracy theory: We never landed on the moon and it was a cold war era propaganda stunt.

***Photo taken on ‘moon’ of US Flag with earth behind it: http://www.mcmahanphoto.com/ns506.html

2007-08-30 02:00:10 · 14 answers · asked by Anonymous in Astronomy & Space

My boss needs to settle an arguement with a friend. Why does the water flow down a plug hole one way in the Northern Hemisphere compared to the opposite direction in the Southern Hemisphere?

2007-08-30 01:58:53 · 5 answers · asked by sugar blonde 1 in Earth Sciences & Geology

2007-08-30 01:57:06 · 10 answers · asked by Anonymous in Astronomy & Space

2007-08-30 01:56:35 · 3 answers · asked by sassy050205 1 in Chemistry

2007-08-30 01:55:37 · 8 answers · asked by prajwal p 1 in Botany

My boyfriend caught a spider (hobo) i think, he put other large spiders he found in with it and found that it had eaten them, are some english house spiders poisonous or do alot of them bite?

2007-08-30 01:53:22 · 9 answers · asked by loopy d loop 2 in Zoology

What could have caused the natural nuclear fission reactors, in Oklo, Gabon, 1.5 billion years ago?

2007-08-30 01:47:39 · 7 answers · asked by Jim 7 in Earth Sciences & Geology

2007-08-30 01:26:58 · 3 answers · asked by Seadog 3 in Engineering

1) find the angle between the lines y=2x+1 and y= -3-5
what are the steps to find the answer?

2) simplify: (1-cos^2x)(1-cot^2x)
??? please help me!!

2007-08-30 01:25:49 · 2 answers · asked by Anonymous in Mathematics

2007-08-30 01:22:49 · 10 answers · asked by iceman_28 1 in Astronomy & Space

2007-08-30 01:22:08 · 5 answers · asked by icey27choco 1 in Physics

can't think of any other questions to ask.

2007-08-30 01:21:57 · 6 answers · asked by TelecomsTowerGod 4 in Biology

2007-08-30 01:20:54 · 5 answers · asked by Bill W 【ツ】 6 in Physics

2007-08-30 01:18:54 · 9 answers · asked by Bill W 【ツ】 6 in Astronomy & Space

2007-08-30 01:16:52 · 3 answers · asked by Anonymous in Medicine

2007-08-30 01:13:34 · 3 answers · asked by emz e 1 in Physics

I have some great photos of it

2007-08-30 01:12:06 · 4 answers · asked by Anonymous in Astronomy & Space

I just want to know.

2007-08-30 01:05:02 · 4 answers · asked by Jasmine J 1 in Zoology

2007-08-30 01:03:18 · 3 answers · asked by lzbth_dannn 1 in Earth Sciences & Geology

What is the easiest method for solving angle of elevation questions?

2007-08-30 01:02:54 · 1 answers · asked by journey 1 in Mathematics

Fact or Theory?

2007-08-30 00:57:45 · 14 answers · asked by Jim 7 in Other - Science

Specifically, metric bearing locknut shaft dimensions. I have all kinds of data on THREADS PER INCH

2007-08-30 00:57:03 · 2 answers · asked by debsmygirl 1 in Engineering

I just want to know...

2007-08-30 00:39:36 · 6 answers · asked by -'mcr fanatic'- 1 in Biology

To compress air, do you just put more and more air into a container? Its just that I have difficulty imagining compressors just pushing more and more air into a container. Is this what happens? Or is there something else involved?

2007-08-30 00:35:24 · 5 answers · asked by Anonymous in Engineering

Im just curious. I know that an unfit or overweight person will have a layer of fat around their heart, but I was wondering if people that are definitely not fat or unfit, for example, an athlete - lets say a runner or hurdler, will have a layer of fat around their heart.

2007-08-30 00:32:07 · 3 answers · asked by Anonymous in Medicine