David

I have used the equations Z = V/I (impedance = voltage / current at the lowest current value) and Z = L/CR (where C=L/(r^2 + XL^2)) (impedance = inductance / capacitance x resistance) to calculate the impedance but both give me different answers.

Why are the two answers different although they are working out the same thing?

I would be very grateful if someone could help me resolve this as i have no idea which is correct.

Question: Is there such a thing as 'Incompressible Aerodynamics'?

A. No, as air is a gas and as such is always compressible. Density changes are always dominant and therefore it can't exist

B. Yes, but only if the flow speed is low enough, so the changes in density can be neglected. This is the case for Mach numbers below 0.3.

In my opinion both answers are correct as, in theory, it does exist but in reality it can't exist as the density is never constant, but, as it is a multiple choice question, only one answer can be correct.

I would be very grateful if someone could help me on this as I just can't seem to come to a conclusion..

An airline company accepts bookings for 20 executive class seats on a flight from London to Bergen. The probability that a customer, who has booked an executive class seat, will not turn up is 0.15 and may be assumed independent of the behaviour of other customers.

The airline also accepts bookings for 50 standard class seats on the same flight. The probability of a customer, who has booked an standard class seat, will not turn up is 0.08 and may be assumed independent of the behaviour of other customers.

The aeroplane has 19 executive class seats and 48 standard class seats. If 19 or fewer customers who have booked executive class seats turn up they will all be allocated executive class seats. If all 20 customers who have booked executive class seats turn up, one will be allocated a standard class seat. this will leave 47 seats available for the 50 customers who have booked standard class seats.

calculate the probability that there will be standard class seats available for all those who turn up having booked standard class seats.

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I have tried various different attempts to answer this but my answers are all over the place. I would be very grateful if someone could show me how to do this question as i just can't seem to get it right.

I remember one episode on about Christmas time in late 90's or early 2000's. I remember on of the characters going into a bookshop and finding a book. they then wish for a green monster which then appears and goes around the town terrorizing the people. The monster soon realizes he is lonely and leaves. we next see him on an ice rink and the song 'Marble Halls' is playing in the background. At the end, everyone comes together and buys him a red car.

I keep thinking it was called something like 'The Bookshop' or 'The Magic Book'.

Can anyone tell me what this was called as it is driving me crazy remembering it?

The questions are:

Solve these inequalities:

a) (2x-5) / (x+1) < 1

b) (2x-7) / (x+5) > 4

I have no idea how you would approach these. I would be very grateful if someone could help me and explain fully how they got the answer.

The questions are:

Solve these inequalities:

a) (2x-5) / (x+1) < 1

b) (2x-7) / (x+5) > 4

I have no idea how you would approach these. I would be very grateful if someone could help me and explain fully how they got the answer.

Using an example of data that could sensibly be stored in each data type, compare the amount of memory required to store a character with the amount of memory required to store a string.

there are 6 red counters , 3 white counters and a blue counter in a bag. if a counter is chosen at random, noted down and placed back into the bag. find the probability that both choices are red?

Probabilities =

red = 6/10

white = 3/10

blue = 1/10

so would the answer be 12/20 ? , confused!

just a random question i thought up but i can't find the answer.

when hydrocarbon fuels burn in plenty of air, what are the two main products?

i know the answer to this (water and Co2) but it's the following question that i need to know, it is linked with this one:

what other substances can be producedwhen hydrocarbon fuels burn in plenty of air?

i have found this coding:

<script language="JavaScript1.2">

function checkpostal(){

var re4digit=/^\d{4}$/ //regular expression defining a 4 digit number

if (document.myform.myinput.value.search(re4digit)==-1) //if match failed

alert("Please enter a valid 4 digit number inside form")

}

</script>

<form name="myform">

<input type="text" name="myinput" size=15>

<input type="button" onClick="checkpostal()" value="check">

</form>

i'm supposed to add it to the following coding so the examination number will only be accepted when its 4 numbers long. how do it. here is the coding:

<html>

<head>

<title>Exam entry</title>

<script language="javascript" type="text/javascript">

function validateForm() {

var result = true;

var msg="";

if (document.ExamEntry.name.value=="") {

msg+="You must enter your name \n";

document.ExamEntry.name.focus();

document.getElementById('name').style.color="red";

result = false;

}

if (document.ExamEntry.subject.value=="") {

msg+="You must enter the subject \n";

document.ExamEntry.subject.focus();

document.getElementById('subject').style.color="red";

result = false;

}

if (document.ExamEntry.Examination_Number.value=="") {

msg+="You must enter the examination number \n";

document.ExamEntry.Examination_Number.focus();

document.getElementById('Examination_Number').style.color="red";

result = false;

}

if(msg==""){

return result;

}

{

alert(msg)

return result;

}

var re4digit=/^\d{4}$/ //regular expression defining a 4 digit number

if (document.ExamEntry.Examination_number.value.search(re4digit)==-1) //if match failed

alert("Please enter a valid 4 digit number")

}

</script>

</head>

<body>

<h1>Exam Entry Form</h1>

<form name="ExamEntry" method="post" action="success.html">

<table width="50%" border="0">

<tr>

<td id="name">Name</td>

<td><input type="text" name="name" /></td>

</tr>

<tr>

<td id="subject">Subject</td>

<td><input type="text" name="subject" /></td>

</tr>

<tr>

<td id="Examination_Number">Examination Number</td>

<td><input type="text" name="Examination_Number" /></td>

</tr>

<tr>

<td><input type="submit" name="Submit" value="Submit" onclick="return validateForm();" /></td>

<td><input type="reset" name="Reset" value="Reset" /></td>

</tr>

</table>

</form>

</body>

</html>

what is the name of a chemical reaction that cant be undone? eg quicklime and water

Need help with a Chemistry homework question please , if three elements in the same column in the periodic table , what does this tell us about the reactions of these three elements ? Thanks

Would any one please be good enough to help me solve this equation ?

2 (a -1 ) = b (1 - 2a) Making A The subject of the equation PLEASE SHOW WORKING OUT . Thanks

how would you rearrange the equation 3(a+y)=by+7 making Y the subject of the equation???

show workings out

http://www.youtube.com/watch?v=yOKtRJWBFL8

what is the name of the song between 5 and 20 seconds of this video

Someone bought a piece of string measuring 24 inches long , they cut off two pieces both 5 and 5 eighths long , how long was the piece left ??? we know the answer will be 17 and three quarters , but not sure of how to simplify PLEASE HELP

does anyone know where i can download the game Flash Flight Simulator (link: http://fliiby.com/file/763594/8rfgyugbnh.html) as a SWF (Flash) File that actually works. (note the download part on the link doesn't work)

11 weeks ago our 1 year old cat gave birth to 4 healthy kittens.nothing occurred as they were growing up as they had been wormed and flea-ed. about a month ago we gave two away (do note they are all healthy at this point) . just recently we have noticed that the two we are left with have been passing runny greeny- brown poop. the older cat is fine and so are the two we gave away. what could be the problem?

if i were to sell a 1975/76 HMV Stereomaster 2419 that is in mint condition, what is the average price that i will get for it? also where would be the best place to sell it so i get more money for it.