thedarkshade

So you have 4500 rev/min, that's the frequency.You just need to multiply [math]2\pi[/math] with 4500rev/60s. then you'll get [math]\omega=2\pi\frac{4500rot}{60s}[/math][math]\omega=2\times 3.141592654 \times 75[/math] and you get: [math]\omega=471.2388981\frac{rad}{s}[/math], that's the angular velocity! to turn them in linear velocity you use: [math]v=\omega\times r[/math] and then just replace the datas: [math]v=\omega\times r[/math] [math]v=471.2388981 \times 1.50=706.85834715\frac{m}{s}[/math] which means that part you did is right! to find [math]I[/math] you have [math]EK=\frac{1}{2}mr^2[/math] (like swansont said) then you have: [math]I=\frac{1}{2}mr^2[/math] [math]I=\frac{575kg\times (1.50m)^2}{2}[/math] [math]I=\frac{575kg\times 2.25m^2}{2}[/math] [math]I=\frac{19293.75kgm^2}{2}[/math] [math]I=646.875kgm^2[/math] and about kinetic energy [math]EK=\frac{1}{2}mv^2[/math] then you get: [math]EK=\frac{1}{2}mv^2[/math] [math]EK=\frac{575kg \times 706.85834715 (m/s)^2}{2}[/math] [math]EK=\frac{499648.7228J}{2}[/math] [math]EK=249824.3614L[/math]

Well, I do not know your interests or what really you intend to achieve in life but Phy/Math is something very very special. I mean, by studying them you really get a sense of knowing what the world really is, why everything is the way it is, why everything happens and what makes them happen. You just know the world! You don't get stuck at anything and you feel like you really belong here. I'd strongly recommend Phy/Math!

It's very interesting to note that where I live (Kosova) intelligence coefficient is usually high. Students who have the chance to go abroad to study they always achieve a very high scale of education. but the strangest thing is that MATH and PHYSICS are the two subject that completely lack interest. Sometimes I really need someone to discuss about them but frankly speaking there are just doctors, pharmacists economists and no physicist nor "mather's", so my "hunger " of math and physics just keeps peaking. So math and physics where I live are just NOT having a good period!

Glad to be useful!

Oh , ok then,, the formula I posted above is the correct one, if you've watched the video, it clearly tells you even the derivation.

the video gives you a good explanation related to energy,, so it might help on that part! WHAT IS WRONG??

The formula for linear kinetic enery is:[math]KE=\frac{mv^2}{2}[/math] and for rotational kinetic energy just instead of m put momentum and instead of v put omega (angular velocity)

http://www.youtube.com/watch?v=Vn32inxsChc try this!

OK ok, thanks a lot for all this!

yes ,that's right but the solution [math] x \in (-\infty , -2) [/math] doesn't work for the left side, because you get log of negative numbers, but it does work for the right side!

But HallsOfIvy was referring to the equation [math]\ln{(x-1)} - \ln{(x+2)} > 0[/MATH] but the real equation is:[math] \ln(\frac{x-1}{x+2}) > 0 [/math] and my teacher said it's right, and IT IS right! he's got a PhD you know!!!

You can do that on your own notebook, it's nothing hard! I watched it and did not really saw a mistake. And it doesn't mean that S2^2 should always be less, it can be less in S1 than in S2, it doesn't really matter, they just have to differ.

Take a look at this video and the way that the equation is derived. It seems to be OK, although it's a bit different from the standard one: http://youtube.com/watch?v=tjv5NYItg1w Is it?

Wait a minute,, of course [math] x \in (-\infty , -2) [/math] is the solution. I mean take -3 for example and we'd get: [math] \ln(\frac{-3-1}{-3+2}) > 0 [/math] and then: [math] \ln(\frac{-4}{-1}) > 0 [/math] minus on both sides of fraction gives you plus, so we get: [math] \ln(4) > 0 [/math] and that's it!

Well, you really seem to be mad at a few things! Everyone agrees that physics nowdays has reached its peak in human history. Physics today gives you very rational explanation of almost everything that eye can see or even smaller than that. Physics today is changing the way of thinking critically about the world and everything around us. sorry but there are mathematical facts than strongly support above mentioned things. If they were "nonsense" as you say, then why would the most brilliant brains on earth be concerned about them. I think here lies another problem, and the problem is that you seem not to really understand them, and that may give you second thoughts about nowdays physics. What modern physics has done, is that it has made a revolution in the way of thinking what world really is, and that is pure science!

I think there is something tinnier that quarks, so in a way, they're seperable! I just don't remember the name!

I guess after all what's said there is very little say, but I'll try to add more. (sorry if I post anything that's been said earlier, I just have no time to look them) OK! Electrons, like said above, orbit the nucleus in orbit which can contain a certain number of electrons. The first shell contains 2 electrons, second contains 8 electrons and so on. You can find the number of electrons in different shells by using the formula: [math]e=2n^2[/math] e-nr of electrons ; n-shell number Shells are marked with capital letters M N O P etc, and orbitals are marked with s p d f g h (g and h are theoretical). Electrons are 1836 smaller than protons in mass. The mass of and electron is [math]9.1 \times 10^{-31}kg[/math] and the amount of electricity that an electron contains is called "elementary amount of electricity" (because it cannot go smaller) and that amount is [math]1.602 \times 10^{-19}C[/math] Electrons are bonded in different ways with nucleus, and what's interesting is that metal's electrons are bonded very weakly with nucleus, so they can very easily leave the orbit. And this is how conductivity works. Another interesting thing about electrons (also called as miracle) is the fact that electrons are 1836 smaller than protons, but they both have the same about of electricity. Of course, electrons are charged negatively and protons positively, while neutrons have no charge and the serve as a "glue". The forces that keep the particles inside the nucleus of an atom together are called strong nuclear forces, while weak nuclear forces control radiation. Sorry for not being able to post more, but I'm running out of time!

Collecting ourselves???? I don't understand Yes, we hear vibrations, because sound are nothing but vibrations in elastic medium. And sound spread is nothing but the spread of energy from one molecule to another!

EXACTLY, that's what I've been trying to say all the time!

You're welcome mate, I just hope I was useful to you!

The title of the thread is "lowest energy level", you can derive the answer from it. Before reacting, it had a higher energy level, so it had to release some energy to reach this low stable energy level. And the reaction made it possible to release this energy and so reach stability. It's the most logical explanation I can think of right now!

Even an easier one! Mix Chlorine and water and you get hydrochloric acid (HCl) and hipochloric acid (HClO). Cl2 + H2P ----> HCl + HClO

I didn't man! I just helped the guy out by explaining what I knew about the thread. Isn't that what everybody does here?

It's not always one electron, it depends how many electrons does that atom need to complete electronic configuration. The energy is released because of affinity toward the electron. Excitation makes the electron go to a higher level, then it releases the energy (which ur talking about) and then returns to that previous level, becoming stable.

Listen iNow. Everybody know that when people are born they have instincts, because if they didn't have them, they'd be just like robots without batteries. When I said blank, i was referring to mental abilities, ability to have an understanding of the world. And what does a 2 days old baby think about the world? Nothing, because his brain blank!!! Happy?