Primarygun

When a car accelerates towards the positive side with 3m/s^2. We have many different ways to state it. Therefore, I think positive number is equal to negative number if we change the "side".

How about when solving movement questions. What's the acceleration of the car? -3m/s,-5/s It's -2m/s^2 or 2m/s^2 towards the negative direction. So related to negative and positive questions?

My mother works and I seldom see her. How special I am?

I found the answer for question one is "no" and question 2 is "yes". I don't think so.Therefore, I put them here.

I moved into some other forums and looked at some question. There are two questions I cannot explain them clearly althought they maybe very simple. 1.Do a wheel and a ship have the same kinetic energy (same mass + same velocity)? 2.Mass of a thing increases when there is collision with that thing.

My teacher said that carbon compounds tend to have molecular structure but silicon compounds tend to have giant covalent structure. How to explain it and is the compound consist with germanium all get the giant covalent structure?

lol.................

Will the space trip for bringing mineral and some useful materials back to the earth be created later?

Do the electrons move from the sky towards the ground or just the electric shield move? I know that a closed circuit, the electrons only move a very small step, but the shield move with the speed of light. Is this determined by the voltage? Is the charge difference also considered(like the sky and the ground)?If so, why doesn't lightning act go to the upper?there is a larger difference of the charge./

Thanks. How does the food stored in central vacuole move to the mitochondria to release energy

I am curious of how cells can store food as granules, how cells can absorb water,how nucleus can control the cell activities and how would the glucose store in one cell. Can everyone tell me? Moreover, I want to question about whether xylem has cytoplasm , cell membrane or mitochondria.

Really?

thanks. why is fluorine gas is still so reactive? Isn't it stable? with a stable octet/.

Does everyone have an experience of burning an aluminium foil? Aluminium powder burn and sliver sparks are observed,but is not for aluminium foil. Is aluminium foil=tin?

Can I made a conclusion of all fluoride compound resist corrosion form HF?

i think yes

Sorry, I mistyped something. it should be [MATH] \sqrt{x}^2[/MATH]

Does SiF4 resist corrosion from hydrofluoric acid?

What will happen if we throw a can into sky? There is no closed circuit. Is the can safe?

I found that my text book's illustration of the glass atoms as silicon oxide, but it said that glass is formed by silicon dioxide. Which is correct?

Which will the lightning choose to pass the water or the land?

Is a man more dangerous swimming in pool(floating) or staying on ground(touch land) when there is lightning? Will the situation change when it is sea water?

Thank you.

Wanna question on the water molecule. Is the part near the oxygen atom so negatively charged made by the Dipole-Dipole bond+ the two lone pairs ?

Ionic compound decomposes when polar molecules attract them. How about non-polar molecules? What forces make the non-polar molecules dissolve in non-polar molecules solvent but not in polar?