your calculator is wrong, either that or you didn't key in properly

wow, this thread is going through a second recession

Originally posted by youyayu:

i wondering should i cont study or set up my own business =X

continue study while setting up a business.

Get a degree to train yourself, but dun rely on it to retirement

Originally posted by crimsontactics:

But knowledge which has no use to your career is till useless. Not everyone aspire to be a teacher.

shu dao yong shi fang hen sao

Originally posted by Daisuke-kun:

how do u explain dis

LOLOLOLOL

A maths binomial theorem:

Write down and simplify the first three terms in the expansion of (1 - 2x)⁸ in ascending powers of x. Given that the first three terms in the expansion of (1 - ax)² (1 - 2x)⁸ are 1, -8x, and bx², calculate the values of a and b.

Originally posted by maurizio13:

 

i have this feeling that quite alot of the questions could be posted by tutors.

 

 

And I just sit around copy questions for ExamWorld?

this thread very good for me to put on examworld :D

but I haven't put yet... these few days concentrating on increasing physics questions

photoshop to create pictures damn fun... This one nice hor:

I just checked the SEAB website

# Last year of exam in 2009.

Wonder what they going to change now...

there might be something brewing with the banks issuing so many preference shares suddenly...

doesn't sound very good

volunteer tuition can always help out at homework forum :D

P***: The chicken crossed the road because it is retarded

the chicken cross the road earlier in the morning to avoid ERP

go study O levels la

Originally posted by iamapebble:

Hey eagle, thanks for your add on :D I get the part on induction and AC generator already! =) But I'm still curious about this:

- DC Motor. We all know to increase the turning effect, we have to

1) Increase the current supplied.
2) Insert a soft iron core within the coil.
3) Increase the number of turns of the coil.
4) Use a pair of stronger magnets.

For number 2), I understand that it is to concentrate the magnetic field lines, but I don't really know how to put it across properly, like, do I say it is because when the lines are concentrated that the "field is stronger" or do I mention about how "more lines are linked to the conductor"? =/ Both sounds wrong T.T

As for 1,3 and 4, I have seriously no idea.

 

Hi

The induced force is directly proportional to the magnetic field and current (paiseh, I forgot the exact formula at the moment).

Visualise one more thing. When there's current in a coil, there's a circular magnetic field. This magnetic field interacts with the magnetic field of the magnets and results in a force. Thus, the stronger these two magnetic fields are, the larger the repelling, or attractive, force.

In short, all of the above actually serves to increase the magnetic fields one way or the other....

Anyway for O levels, I'm not sure if you need to really explain the above...

For that stupid forumer who told me wiki can definitely be trusted, yet want to believe in Singapore, this article should make him eat back his words even more

The Government of Singapore Investment Corporation Private Limited (GIC) is a sovereign wealth fund established by the Government of Singapore in 1981 to manage Singapore's foreign reserves. With a network of eight offices in key financial capitals around the world, GIC invests internationally in equities, fixed income, money-market instruments, real estate and special investments.

GIC's investment portfolio is managed by its three subsidiaries: GIC Asset Management Pte Ltd (public markets), GIC Real Estate Pte Ltd and GIC Special Investments Pte Ltd (private-equity investments).

In 2007, GIC invested S$14 billion foolishly in UBS, a bank whose value has plunged over 60% since that time, meaning that a . S$8.4 billion dollar loss has already been inflicted on Singaporeans.


GIC's stake in ICICI Bank of India, originally hugely profitable, has bungee-jumped 74% down from a peak of 1400 rupees, turning their originally profitable investment into a loss-making one, taking into consideration their average down cost since 2007.

Its sister company Temasek, fared even worse, with a 70% plunge in the value of Merrill Lynch, and a 59% plummet in the value of Citigroup. Even Standard Chartered, supposedly the most stable in the Government's portfolio, has sunk 33.4% based on Friday Oct 10th's closing price of 999.5 p.

Temasek committed another heinous fiasco down under, losing almost S$500 million in the bankrupt ABC Learning after buying at the peak in 2007.

It's also famously losing a vast proportion of its US$3 billion in Shin Corp of Thailand, after the shares plunged over 60% due to Thais' objections and it therefore facilitated an illegality(tax evasion by the former owner Thaksin Shinawatra). Also, it has to pare down its stake to 75% in a falling market.

Due to the recent market selldown, the value of Temasek and GIC's holdings in GLCs like SIA, DBS and such has also plummeted by S$40 billion.

This makes the grand total of deterioration in the Singapore government's portfolio close to S$80 billion, necessitating a hike in transport fares, ERP charges and utility rates to recoup their losses. In 2008, The Economist reported that Morgan Stanley had estimated the fund's assets at US$330 billion, making it world's third largest sovereign wealth fund.

http://en.wikipedia.org/wiki/Government_of_Singapore_Investment_Corporation

It is Woodleigh station

a train boarding station for the lost souls of the cemetry they dug up to build this station

sometimes, those cleaners clear away the trays and plates before we even finish the dishes...

They so garang, how we clear ourselves

hi ahm97sic

the terminology is incorrect

means a and b are the lower limit and upper limit of the integration

It means integrating from x = a to x = b

This is because

Going the other way round, you will have to put a negative sign.

Integrating from x = 2 to x = 0 is equal to the negative of integrating from x = 0 to x = 2

Originally posted by purpledragon84:

u really cant understand what im saying can u? for all that delusional talk about ur supposed superiority, u cant read a simple line of text..

i thot i found someone competent enough.. i guess i was wrong afterall..

guess i have to look again..

oops. full time.

Purpledragon 1 Parn 0..

 

At first I thought too that she had some substance.

But then, she proved me wrong later by a great show of brainlessness and spoilt brat attitude

ahm97sic, from your answer, I think you should phrase it as integrating from x = 0 to x = 2

Not the other way round :D

Originally posted by Garrick_3658:

So, it's like you're totally ignoring the modulus sign? Since modulus reflected the graph to positive shouldn't your area be positive too?

that's because the integration is from 2 to 0, not 0 to 2

sigh... last time my sec school gave a series of number patterns question... had 25 of them...

I used it to teach tuition, but left it with a tuition student very long ago, and it's gone :(

well done everyone

Ganbatte!!!!!

Originally posted by Garrick_3658:

I'll have to TRY to answer the others later. I am a Secondary Four student (Triple-Science, Elect Geog) too, so pardon me if i make any mistakes.

- AC Generator. The purpose of the slip rings as it states in the textbook is so that "the alterating induced current in the coil is transferred to the external circuit". So does that mean that without the slip rings,  the induced e.m.f is lost to the surroundings or does it keep 'flowing' throughout the coil? And according to a longman assessment, they stated that the purpose of the slip rings is so as to prevent the coil from entanglement. So what exactly is the correct explanation?

Slip rings ensure that the direction of the induced e.m.f./current flowing in the EXTERNAL circuit changes every half revolution (that is, every 180 degrees turn) to produce an ALTERNATING CURRENT (main purpose of A.C. GENERATOR)

The purpose of the slip rings as it states in the textbook is so that "the alterating induced current in the coil is transferred to the external circuit". So does that mean that without the slip rings,  the induced e.m.f is lost to the surroundings or does it keep 'flowing' throughout the coil? I don't know about this. This is very vague and debatable (induced current flows in the cables).

The Longman Book is not wrong to say prevention of coil entanglement, because without the slip rings, try to visualise if you were to turn the coil. How would the connecting cables in the EXTERNAL circuit be affected? Or rather, how would the external circuit, on a whole, be affected?

 

- Charges. For example, if a positively charged conductor is allowed to come near the left of an neutral object, the electrons in the object will be attracted to the left and the protrons will be repelled away to the right side. Thus, there will be attraction between the conductor and the object but once they touch instantaneously, some of the electrons were transferred to the positive conductor thus causing the object to become positively charged (since it lost some electrons) and repel away from the positive conductor, right? Then why is it for example in crop-spraying it states that the positively charged droplets induces negative charges on the plants as they come closer to the plants, allowing attraction. So, when do I know it's induction or something? And when the droplets reach the plants, does that mean that the plants become negatively charged or positively charged?

the electrons in the object will be attracted to the left and the protrons will be repelled away to the right side. The protons don't move. It is very easy for them to find fault with you if you say that the protons are repelled to the right (although it is not wrong to say so). Just state that electrons are attracted to the left and the protons are LEFT at the right, INDUCING the right side with a positive charge (and vice-versa).

to become positively charged. To be INDUCED with a positive charge (though I can't find any difference, but my teacher emphasised on using this)

Then why is it for example in crop-spraying it states that the positively charged droplets induces negative charges on the plants as they come closer to the plants, allowing attraction. So, when do I know it's induction or something? And when the droplets reach the plants, does that mean that the plants become negatively charged or positively charged? What textbook does your school use? Mind uses the Pearson Longman Physics Insights, 2nd Edition (no sorry, I don't have a scanner). Mine gives an example on Electrostatic Paint Spraying. I think you just have to understand that induction precedes attraction. Induce negative charges on plant --> attraction --> charges between droplets and plant are neutralised (since they come into contact) --> electrically neutral plant.

Very very well done. You are well on your way to an A1 :D

I shall add on a bit

The purpose of the slip rings as it states in the textbook is so that "the alterating induced current in the coil is transferred to the external circuit". So does that mean that without the slip rings,  the induced e.m.f is lost to the surroundings or does it keep 'flowing' throughout the coil? I don't know about this. This is very vague and debatable (induced current flows in the cables).

Without slip rings, or rather, without a complete circuit, there will be no induced current. Rather, there will be an induced voltage.

The reason is because of the force on the moving electrons. When wires move in a magnetic view, you can visualise lots of electrons moving in the wire moving in the field as well... Something like that... There will be a force on the electrons to move to one side, and hence creating a potential difference. If it is a complete circuit, these electrons will continue to move in the circuit, resulting in the induced current :D