Science & Mathematics - 5 September 2007

plz help

2007-09-05 09:32:54 · 7 answers · asked by Anonymous in Mathematics

The diode, a very common two-terminal nonlinear device, can be modeled using the following current-voltage relationship:

I = 10^-9 * ((e^39V) - 1))

1) what is the effective resistance of the diode at V = 0.55 V?
2) at what current does the diode have a resistance of 1 Ohm?

answer 1 = 266 mΩ
answer 2 =514 mA

how????

2007-09-05 09:30:15 · 4 answers · asked by lennox lewis 1 in Engineering

square root of x+5= 1+ the square root of x-2

2007-09-05 09:30:14 · 3 answers · asked by brandtster 2 in Mathematics

1) What distance does a car travel if it moves due north at 50km/h for 2 hours, and then due south at 50km/h for 2 hours?

2) What is the cars displacement (from the above problem)?

I'm not exactly sure what the answer for this problem is. I mean, logically I think it would be zero..but in the back of my mind i'm thinking that that is not correct..any help here?

As for the displacement, if my answer is correct, which it probably isn't..it'd be zero..but I don't know!!

2007-09-05 09:27:43 · 3 answers · asked by Anonymous in Mathematics

2007-09-05 09:21:29 · 10 answers · asked by Greymatter 1 in Weather

2007-09-05 09:20:04 · 4 answers · asked by silva 2 in Mathematics

i need help with this this question for Math class in 6th grade help please !

2007-09-05 09:17:56 · 5 answers · asked by pk 1 in Mathematics

Example: At which grade do middle school students carry the heaviest book bags? Hypothesis: If students are in higher grades, then their backpacks will be heavier, because they have heavier textbooks.
Problem: Which class is easier to pass, math or science? What would the hypothesis be?
Problem: What side of the classroom is warmer? What would the hypothesis be?

2007-09-05 09:16:16 · 1 answers · asked by Anonymous in Mathematics

2007-09-05 09:15:49 · 6 answers · asked by Anonymous in Mathematics

She has one uncle that lives in Japan and one that lives in S. Africa. I need a simplified explanation of this.

2007-09-05 09:13:21 · 6 answers · asked by Karen 2 in Weather

give the x and y components, magnitudes, and directions of the following vector operations:
a + b
(x component)
(y component)
(magnitude)
° (direction from the positive x axis)

2007-09-05 09:13:00 · 1 answers · asked by tosinjesu 1 in Physics

Were to find on the internet the Periodic Table of Mendeleev that has in every square the name of element the short name the atomic number ????? Please need for school starts in 17 or 14 septembre . To print it . Need for portofoliu at chemistry.Don't know if I said good in english.

2007-09-05 09:12:34 · 5 answers · asked by dragoi_stefan06 2 in Chemistry

2007-09-05 09:12:27 · 3 answers · asked by Rick R 1 in Earth Sciences & Geology

3(x-4)=2x+7-3x

thank you Im really lost on this problem...

2007-09-05 09:05:31 · 3 answers · asked by kawaii_dumpling 1 in Mathematics

2007-09-05 09:04:58 · 7 answers · asked by Alexander M 1 in Engineering

Okay so some of you will probably think this stuff is easy but i just don't get it. If someone could please give me step-by-step instructions on how to figure out one/both of the following questions:

1. If john invests $2300 in a savings account with a 6% interest rate compounded annually, how long will it take until his the account has a ablance of $4150?

2. Determine how much time is required for an investment to double in value if interest is earned at the rate of 6.25% compounded annually.


And on a side note, I have the equation A=P(1+r/n)^nt - if i fill in the numbers that I know, how do I solve it if the variable is in the exponent?

2007-09-05 09:03:35 · 3 answers · asked by dunkn_donut 1 in Mathematics

Bruce wanted to run the Shore-to-Shore marathon next month, a 26-mile race from one side of the island where he lived to the other. He decided to work up to 26 miles by running five days a week for the next five weeks. Each day he'd run one mile longer than he did the day before, except for the first day of each week, when he'd run the same number of miles he ran on the last day of the previous week. He wanted his last to practice runs to be 26 and 27 miles long.


How many miles would he have to run on the first practice run?

2007-09-05 09:01:47 · 2 answers · asked by Anonymous in Geography

negative 4 square root of 1 + cos2x..plz help with pre cal

2007-09-05 09:01:37 · 4 answers · asked by silva 2 in Mathematics

please show me step by step

2007-09-05 08:59:53 · 6 answers · asked by AnswerGirl 2 in Mathematics

plz help with pre cal

2007-09-05 08:57:49 · 8 answers · asked by silva 2 in Mathematics

What is the latitude and longitude of Shanghai, China?

Thanks!

2007-09-05 08:57:17 · 2 answers · asked by Anonymous in Geography

Let's say theres a light at the bottom of a bicycle wheel and we were to turn off the lights in a room and push the wheel across the room. what shape would the trajectory of the light make in one revolution of the wheel. i think it'll make kind of a flatened parabola, but im very visual and it's hard for me to imagine. My teacher only told us that the wheel has a diameter of 64 cm and the trajectory would be a specific shape but he would only tells us after we tired to figure it out, but i'm curious and i want to be a little smart *** and find it out first. If i need to clearify or add details just ask me! thanks

2007-09-05 08:54:12 · 3 answers · asked by stefany 1 in Physics

Just a first day of school assignment question that I need a few examples of by tomorrow. Any examples would help!

2007-09-05 08:53:04 · 8 answers · asked by Alex 3 in Biology

2007-09-05 08:52:50 · 2 answers · asked by Anonymous in Mathematics

2007-09-05 08:52:49 · 5 answers · asked by me 1 in Zoology

ok, i have to to find the formula for

1/2, 2/3, 3/4, 4/5

I'm not sure, but i think its something like

n squared divided by n +1
But that doesn't seem to be right.

Help?

2007-09-05 08:49:49 · 4 answers · asked by Rach 2 in Mathematics

Dennis plans to use 1150 ft of fence to enclose the rectangular pasture. One side borders a river where there is already a thick hedge it needs no fencing.
The diagram is a rectangle with width x.

a. let x be the width. write an expression for the length in term of x
b. write an expression for the area of the pasture in terms of x
c. suppose the pasture must enclose at least 60,000 sq ft. write a sentence (as a sentence in math not a sentence like this one.) relating the area expression in part b to the area the pasture must enclose.

I have a and b but i want to check them since they're related and i completely don't understand c, can you clear thing sup a bit for me?

2007-09-05 08:46:49 · 2 answers · asked by Salivating Fish 3 in Mathematics

!. addition
2. subtraction
3. division
4/ mulitiplication

2007-09-05 08:46:33 · 8 answers · asked by David C 1 in Mathematics

2007-09-05 08:43:33 · 5 answers · asked by Anonymous in Biology

My daughter is in a required Biology class and is a sophomore in H.S. Her teacher who is new this year had them bring in a live insect...or something without a backbone. Someone brought in a crawdad and the teacher held it up and said, let's see what its tolerance for pain is, and pulled one of its legs off while it was still alive! He was having them poke and prod things while they were alive. This made her heartsick, and her father and I as well. Called principal this morn, and he informed me that all he could do was make sure she was assigned a different assignment, but that he didn't see anything wrong with it. He talked like it was out of his hands and he informed me.."Well, we disect animals" I said, not when they are alive! Hubby talked to Superint. and he says he will look into it. What is your view? Do you think he is encouraging cruelty to living things( the teacher)? Do you think the principal handled this right? I think they are cruel. B4 disecting, they should be dead.

2007-09-05 08:43:19 · 22 answers · asked by ShineOn 4 in Biology