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#1 Re: Dark Discussions at Cafe Infinity » relativity » 2006-07-04 01:25:11

MathsIsFun wrote:

And, in fact, I think elementary physics is still taught as if Einstein never existed.

I remember reading "an object will continue to move in a certain direction at a certain speed unless acted upon by another object" (or some such wording). No mention of "relative to bla bla". That just perpetuates our ground-centred view of the world (ie "The ground is fixed everything else moves" which is our normal experience). But in reality the ground we stand on is just another part of the universe and could itself be considered to be moving if oserved from that object.

do you mean 'every object will continue in it's state of rest or uniform acceleration unless acted on by an external force'
That is Newton's first law of motion. I had to do about the laws of motion for the mechanics part of my physics A/s. We were taught that they only apply on the earth, where motion will be relative to the earth.
I also had to do a bit about it in GCSE physics. I think that relativity would not be understood if taught at an earlier level, or have to be simplified for people to get any grasp of it.  At GCSE my teacher only went throught the stuff about expanding universe to a very small group as it would have confused most people. I think more complecated areas of the subject should be left to a higher level. simplifying it does not work, when i moved from GCSE to A level I got so confused as I had be taught stuff that had been so over simplified it was basically wrong.

#5 Re: Guestbook » Hey » 2006-06-13 18:08:20

Thanks. I have trouble understanding when people type like that

#6 Re: Guestbook » Hey » 2006-06-13 01:48:50

Can we have this in english please?

#7 Re: Dark Discussions at Cafe Infinity » World Cup 2006 » 2006-06-12 06:24:20

I am trying to avoid it, as people have gone crazy about it where i live. I got into maths this morning, (I am the only girl in the class) and all the boys were taking tatics, and players and I didn't have a clue about it.:o

#8 Re: Puzzles and Games » Ninja's Puzzles! » 2006-06-05 18:48:58

I think it depends on where you are going by mass, %, moles etc. There are so many different molecules in the body, that there is probably some dispute about which element is the most common. Personally, I would have gone for carbon, but that was a guess anyway.

#9 Re: Help Me ! » Mechanics 1 - Kinematics Problem » 2006-06-04 18:04:12

The exam is on Tuesday I was getting mixed up with chemistry I have on Wednesday. Ah too many exams

#10 Re: Help Me ! » Mechanics 1 - Kinematics Problem » 2006-06-04 08:53:54

I think I have worked out how to do this.

We know the acceleration is uniform, we will call this 'a'.

Looking at section AB:
S=80m
a=a
t=4 s
u: we do not know this, I will call this y
V:we do not know this, I will call this x

Looking at section AC:
S= 140
a = a
t =6
u= y
v we do not know

Substituting the values of AB into s = ut + 1/2 at² gives
80= 4y + 8a
dividing by 4 gives
y = 20 - 2a
This will be equation 1

Substituting the values of AC into s = ut + 1/2 at² gives
6y + 18a = 140
this will be equation 2

Substituting into 2 gives
6(20 - 2a) = 140
a = 20/6 = 3 1/3

Substituting back into equation 1
y=20 - 2x20/6
y= 13 1/3

Hope this helps. Are you doing the M1 exam on wednesday? I have the same text book, so found the question and checked my answers against the give answers.

#11 Re: Puzzles and Games » Ninja's Puzzles! » 2006-06-02 22:32:18

Although water is the majority of the body there are a lot of other molecules which could make a difference. Sugars are made up from carbon, hydrogen and oxygen. An alpha glucose molecule contains 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms. Carbohydrates are long chains of sugar molecules. Amino acids (which make up proteins) contain an amino group - NH2, a carboxylic acid - COOH, a central carbon atom, an additional H, and an R group. The R group can consist of different amounts of C, H and other elements such as sulphur. Then there are lipids (fats) - triglycerides and phospholipids. A triglyceride consists of a glycerol molecule and 3 fatty acid molecules. The glycerol is C3H5(OH)3 and a fatty acid has a hydrocarbon chain and a COOH group. A phospholipid has a phosphate group instead of one of the fatty acids. Phospholipids make up the cell membrane.
After that description of some of the molecules in the body, i still don't know which element is the most common. It depends if you are doing it by number of atoms, moles, relative atomic mass, or grams.

#12 Re: Dark Discussions at Cafe Infinity » do you procrationate? » 2006-05-29 04:56:37

I only ever seem to have the urge to tidy my room or do some gardening when i have lots of work to do. Actually, pullling out some really stubbon weeds is quite satisfying if you are really stressed with revision.

#13 Re: Dark Discussions at Cafe Infinity » Preparing » 2006-05-27 19:56:58

I'm in the middle of my exams at the moment and these are some ways I prepare. They might not work for you, but you can try.

When I am revising I make posters of the key points and stick them around the house in any place my parents don't object to.  If I have a lot of names or terminology to remember I make revision cards, which i can easily carry around with me and look at when I am on the train or got 5 minutes to spare.

When I am revising I will take breaks regularly (maybe every hour). However, if I am practising an exam paper, I will set my self the time and do it straight through. Some peolple say you should take breaks every 20 minutes, but i find it pointless, as you can't get much work done in a session that short.

To decide what to revise if time is short I think of everything I can do well and ignore it. It can be temping to revise the stuff you know you can do, but is also is pointless. I think of my weaker areas and work on them. If I have a lot of past exam papers I will pick out the questions on that subject, try them, then check the mark scheme.
Generally, I find working through past exam papers can be good. You may know how to do the stuff, but if you have practised it one way and the question asks it differently it can be really confusing.

On the night before an exam I never stay up late working. I may read my notes, but normally I will watch a DVD or do something to get me relaxed. Like MathsIsFun, I try to get a good nights sleep.

On the morning of the exam I always have breakfast, even if I am feeling sick I will try and eat something, maybe just some fruit. I arrive early at the exam and sit/stand outside and go over my notes.

During the exam I work steadily and pace myself. If there is a question I am stuck on I skip it. If I feel a bit panicy I stop, take a few deep breaths and have a drink of water (I don't know if you are allowed to take a bottle of water into your exams).

Also don't do too much revision as all you will do is tire yourself out and forget things. I've been through that, didn't realise I was doing too much at the time, but was really exhausted afterwards. For me it was trial and error finding out how much i can do.

I hope some of this helps, and good luck with your exams.

#14 Re: Guestbook » C1 C2 maths exams » 2006-05-23 02:21:07

Thanks. I think it went quite well, got to do my mechanics module in two weeks time and then a long wait for results.

#15 Guestbook » C1 C2 maths exams » 2006-05-21 17:53:06

stardust
Replies: 3

I have my C1 and C2 (AS maths, England, age 17) maths exams in approximately 2.5 hrs. I am very nervous

#16 Re: Help Me ! » Need help solving the 'Who owns the fish?' puzzle » 2006-05-16 02:51:02

Have you tried drawing a tick/cross grid? You might work out something you haven't got, by doing it that way. That was how i solved it.

#17 Re: Guestbook » Math » 2006-05-13 07:51:07

I find with maths that somethimes I will be taught something and find it really boring and pointless, but then later on we will do something else that needs it, and it makes so much more sense and is a lot easier when you have a context for it.

#18 Re: Dark Discussions at Cafe Infinity » imballanced brain... » 2006-05-11 07:14:34

I have problems talking with people. Since I started sixth form college I have found it really difficult as I am talking all sciences and maths and my friends are taking subjects like history and languages and aren't really interested in what I'm doing. When I meet new people and am asked what subjects i do, they never know what to say when i tell them I do chemistry, biology, physics and maths. It seems to be a real conversation stopper.

#19 Re: This is Cool » Yeah! » 2006-05-11 07:10:21

I have my A/s C1 C2 exams on monday. Quite nervous, but i got an A in my C1 mock (still waiting for my C2 mock results)

#20 Re: Guestbook » games » 2006-05-10 04:32:52

I did the tower of Hanoi, but I did with real rings at science museum. I like proximity and Shanghai, but I keep playing them when I should be revising.

#22 Re: This is Cool » May 4 » 2006-05-06 00:33:25

Please, not the star wars may the 4th one. My applied maths (mechanics) teacher is always telling use to 'Use the force'

#23 Re: Introductions » anyone talkin 2 me » 2006-04-28 05:36:49

I'm glad it's not just me confused

#24 Re: Maths Is Fun - Suggestions and Comments » MY suggestions » 2006-04-28 05:29:23

I love doing sudoku, but i wouldn't manage that many in a day.

#25 Re: Jokes » animal jokes » 2006-04-26 06:44:52

I'd heard the second one before, but the first one was funny.

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