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Thank you. Some extension of GSCE.

What keywords will help me a lot?

Are there any web sites which provide lots of practising questions or problems for the maths, physics, chemistry, biology? I'd like to have far more practise during Christmas holiday.

Not putting [Math] \gamma = \pi/2? [/Math]

For 5 con. integer, the reminder is 1,2,3,4,0 = 1,2,-2,-1,0 ( By definition of mod ) Or Sum of reminder = 1+2+3+4+0= 10 which is divisible by 5 [Two approach]

This may be harmful to human body and affect our health, but it is not the most dangerous one apparently.

From the above, I only know of calcium chloride. That's commonly used in some drying agent, like the one you can buy in supermarket to remove the moisture from your house. It is also used in common experiment to ensure an absence of water vapour. However, I suspect whether it does work with a fast rate since my last agent box performed not very well. Perhaps it is fake!

Disconnect from the net can remove that virus?

Yes. Indeed, I need to provide much information. When the screen loaded to the window screen, it restarts again. Sometimes, I click the button to login and it goes into my desktop. It restarts again. I don't think this is the problem of any hardware rushing as I didn't install any more hardware since the last year. I have scanned the driver with both Norton and online Mcfee software. Some virus was found and was removed. I have also used Norton Doctor 2002 to check for errors and they have been fixed so far.

blueing? You mean the rust? Rust disintegrates when it forms, a new surface exposes again/

My computer always restarts when I switched it on recently. I am sure something happened but I can't identify it. Could anyone tell me?

Thank you very much. Is this the property that iron can be made as magnet? Which else metal can also be made as magnet? And, how can a good electrolyte speed up the process? Ions attract the iron atoms leave the solid?

Hello, I want to have a clear mind before taking the exam. Isn't the layer of iron can resist corrosion,.ie. rusting, like zinc and aluminium? Also, why is rust so strange, the rust is red in colour? Shouldn't it be yellow or green in colour?

What's the general formula of nitrogen compound can be absorbed by plant? NH4(X)?

Yes. My book said it is nitrogen-fixing bacteria in the root nodules of legumes. It feeds on the carbohydrate produced by plant, actually decompose them with nitrogen. What's the product of this metabolic reaction? Ammonia?

so ammonia and nitrate ions? By the way, what's the relationship between plankton and zoophyte?

In nitrogen circle, nitrogen-fixing bacteria convert nitrogen into nitrogen compound but not nitrate and can be absorbed by plant,why? Isn't plant only able to absorb nitrate ions?

Hello everybody, I need serious help. Anyone has studied psychology before? I am in a trouble.

How does it contribute greatly to physics? I know it does but I am just learning very basic things

Gilded, be confident! I second you. I hope I will be supported when I take the public examination next year!

During these two months, I found there are far fewer threads interesting and I did a little effort on replying posts. What are everybody doing? You guys seem to be absolutely bored and annoyed.

What are the functions of counterweight in a lift system? I could only know of the advantage when the lift is up. In fact, it is supposed to have lots of reasons.

Up to this moment, I started to learn some concepts in work-theorem. I am not sure what can this theorem bring us, can anyone tell me the uses of this theorem apart?

Thank you. How about a man holding a book is walking, what's the work done on the book by him? Is this should be accounted into the work done by friction but not by the man? Cheers

My teacher said that a box 1kg leave up by a man 50m, then he just said the potential energy= work done , so PE=500 J. The explanation may be a bit vague that cause me think of the work done is by human efforts against the gravitational force. Contradiction arises as F by human not = mg, otherwise, no movement or continuous movement. Here is my illustration. I think that after a certain distance rose, if it is released, the earth pull F=mg , this is the source of the work done. And where have the human efforts gone? Some stored in object as PE, where are the others, KE? and 1.Potential energy is defined as the work done by gravity, right? 2.Energy gain refers to potential energy gains,right? but no kinetic energy gain.