Primarygun

Thank you Mokele. I neglected the intermolecular forces. I just thought of the action-reaction force. It is relative. When you travel in a bus, the people before you seems to be coming while the people behind seems to be leaving. In the case, this is the same.

Yeah GOT IT! Of course not HK. We prefer to say that we are HK people rather than Chinese.

The function of sand is to provide bacteria to digest faeces, isn't it ?

Is it possible to make an alloy ( mixed with carbon also called alloy?) harder than diamond?

Why do drags depend on velocity? Doesn't air resistance depend on the action-reaction force by the object to the air molecules?

After washing, are the bacteria removed?

What else can be used to make magnet?

That's above my knowledge.LOL

Adding carbon to steel makes it harder and stronger. Is this true for all metals? Could you add carbon to titanium or vanadium to make them even harder and stronger? On the contrary, why adding sulphur to metal to give a softer metal? I could imagine there's no chemical reaction.

Why do only iron , nickel and cobalt can be striked to be become a magnet ? Why do other element cannot?

Anyone would like to help my previous question? I'm quite confused.

What happens to the fish if the water is milky with some sand precipitates?

The gravels are silicon dioxide which can be obtained in beach? Is that good for me to put the gravel at the bottom in a ecosphere? Thanks everyone, before your helps, I only thought of the problem of chlorine and the lack of oxygen in water which affect the health of fish.

What's that?

Any of you has fish at home? Can you tell me more about it ? How to remove the chlorine in water? How can I find some micro-organism for the fish to eat? What does fish mainly eat? Why there is a lot of microogranism on the surface of algae?

Yes. The case above shows falling with constant acceleration, but the velocity determine the drag, I don't know why it is determined by the velocity with constant acceleration.

How to bookmark the channel in my favourite? I use the free MIRC.

What's the strongest acid as far as you know in the world? Is nitric acid stronger than sulphuric acid?

Ya the ecosphere is very interesting.

How does the velocity of an object affect the forces?

Thank you

I'm going to make a globe which contains organism, mainly animals and plants. What do you suggest me to put it inside? There is a competition for me. I am required to make them alive as long as possible. No extra things can be put inside after the globe is sealed. I think it's quite like the matters in geography.

I'm quite confused about the force and motion. Force used to determine acceleration. Is the acceleration per second? How to find out how much time the acceleration last for? Come to my case, Air molecules exert force back to the falling object to decelerates it. Why velocity is required to know? Isn't the acceleration constant and the reacting force from air molecules is deceleration? When the sum of them are 0 , the object stops accelerate, but in the equation, why do we need to find out the velocity? I don't know how to account for it but I know it is indeed a factor in reality. Please help me/

In fact, what's a displacement reaction? It is mainly occured in a solution?

Does the mass of the particles contribute the potential energy? Heavier isotopes have a higher potential energy?