  # Curiatron

Members

12

6 Neutral

• Rank
Quark

## Profile Information

• Location
Pacific Northwest
• Interests
Learning new things! At the moment this includes relativity, information entropy, and how to make a good cup of coffee (not necessarily related to each other).

Also interested in computers and programming, hiking, mountaineering, and generally being outside.
• College Major/Degree
BS Civil Engineering
• Favorite Area of Science
Multiple areas
2. Hello! I would love to help you! But, I'm unsure what help exactly it is you need? I do see you are working with context free grammars and the Backus Naur Form, but what areas are you uncertain with? Don't worry if you can't formulate an exact question...we can even start with question 1 and you asking, 'what is a parse tree?'. *incidentally, your questions are quite timely as I'm dusting off my knowledge of parse-trees and languages, as I try to create my own LR(1) based compiler-compiler
3. ## PV=nRT (This is so hard... for me) Chemistry

Interesting problem. Here is my contribution. Hopefully others can critique me too: 1. Problem statement says to assume that none of the air dissolves into the water. Therefore, does the quantity change? Do you then really need to know how many moles there are? 2. Re. your question on knowledge of temperature - look at the left and right hand sides of the ideal gas law equation (PV=nRT). Does a change in pressure and/or volume (left hand side) require a corresponding change to the quantity and/or temperature of the gas (right hand side)? Is there a way that you can keep the right hand side the same while changing the P and V values on the left hand side? For example, if we said the right hand side (nRT) is 6, are there different combinations of P and V that we can find to keep the right hand side (i.e. n,R,T) equal to 6?
4. Can you please clarify what you mean by, "carry their own medium" and "create the medium as they go along"? I read this to mean that light waves propagate outward in a bootstrapping fashion where the next instance is generated by the prior - is this a reference to the photon? If so, then does that mean that movement of a photon is caused by the prior location of said proton?
5. Are you saying that given sufficient time, superimposing random "waveforms" in a trial and error process will generate what someone may consider as music? There are similar examples, such as with text. I recall a certain idea that given sufficient time, a monkey hitting random keys at a typewriter will be able to create a great work, such as that by Shakespeare. Am I missing the mark here? Did you have some sort of deeper idea that you're trying to present?
6. Well, in civil engineering we typically dimension off of the centerline for roads, water channels, and other things that are more or less "symetric" about the centerline. However, sometimes things are not dimensioned off of centerline. For example, sometimes roads have additional alignments, for example, along the road curb because the curb alignment deviates substantially in both the horizontal and vertical directions.
7. Here's a hint: Start by asking yourself, if you understand the syntax required for an ordinary, non-nested loop? Simple Non-nested loop example: do 10 i = 1, 5 i = i + 1 10 continue If you understand the syntax for a non-nested loop, then you can move on to understanding nested loop syntax. Simple nested loop example (loop 20 is nested within loop 10): do 10 i = 1, 5 do 20 j = 1, 2 j = j + 1 20 continue i + i + 1 10 continue If you understand these syntax, then you should be able to answer your question on your own
8. Hi Dekan, In reading your original question, and subsequent follow up response, I see a few misunderstandings that, if cleared up, would help answer your question. The above posters have corrected you regarding your understanding of how to determine a prime number: However, your statement: lead me to also wonder if you have the correct idea of how the binary number system works? No offense is meant by this questioning - purely trying to help here... In the binary number system, you are correct that there are only two "digits" available to express numeric values - the "0" and the "1". You may be a bit confused because "0" in binary is written the same as "0" in decimal. Likewise, "1" in binary is written the same as "1" in decimal. But, the similarity ends there. In fact, we can express any number we wish using a series of the "0" and "1" digits. So, for example, the value 3 in our normal (i.e. decimal) system is expressed as "11" in binary. The value 4 in decimal system is expressed as "011" in binary. Here is one source for more on decimal-binary number conversion: http://www.binarymath.info/decimal-conversion.php If/once you do have an understanding of how the binary number system works, then I would suggest a review of how division works in the binary number system. Here is a link to one source: http://www.binarymath.info/multiplication-division.php You will see that binary division is not limited to only dividing by "0" and "1" as you stated. Rather, we are allowed to divide by any number we wish! It's just that the number we are dividing by is expressed using binary numbers, and thus a series of "0" and "1" digits. Hope this helps! Oh, and remember: there only 10 types of people in this world - those that understand binary, and those that don't!
9. You will be able to determine the answer by writing a small test program that compares the two variables. Psuedo-ish code: Main { int Number = 10 int number = 5 //if Java recognizes N and n as different variables then you will get no error, otherwise you may get an error here. //review output. if Number and number output is the same as what you initially declared then Java recognizes upper and lower case names as different vars. printf("Number: ", Number, " number ", number ) } A general tip - it's been helpful to me when learning a new language to answer these type of questions using similar small test programs.
10. ## Prerequisites for DIY-Learning General Relativity Physics

Hi all, I am interested in learning about general relativity (GR) in a do-it-yourself fashion. To that end, I was hoping that some of you may be able to provide some advice on the following two questions: Am I missing any prerequisite knowledge required before beginning an introductory study of GR? Below is a list of college level math and physics courses that I completed during my engineering undergraduate days (a while ago, but reasonably confident I can brush up on the course material). A good introductory GR textbook - aside from clear explanations, something with lots of examples and worked through problems would be nice. Thanks in advance! Completed Relevant Coursework: Classical Mechanics Physics (i.e. Newtonian stuff) EM Mechanics Physics Multivariate/Vector Calculus Ordinary Differential Equations Numerical Computation Methods Introductory Statistics
11. ## Help with Lorentz Transformation Derivation

Thanks for your helpful responses. It took me a bit to digest your answers, so that's why I didn't respond right away . This is probably a naive question, but are there any other frame invariant speeds that we can apply the Lorentz Transform to?
12. I am trying to teach myself about the Lorentz Transform. I have been using the derivation in  as my resource*. I am able to follow the derivation pretty well, but have some questions on how they got from equation (25) to equation (28). Here is a snippet of the derivation that I'm stuck on: Here are my questions: 1. Regarding equation (26), when would parameter a ever be less than 0? 2. Why is parameter a associated with the speed of light? I don’t understand their explanations for this association, including: a) The derivation explains that parameter a is invariant. I realize that it is well stated that the speed of light is invariant. However, are there any other invariant speeds? If so, then why couldn’t parameter a be identified with one of those invariant speeds? b) The derivation also says a is identified with the speed of light because of Maxwell's equations and electromagnetic waves. What particular properties of Maxwell's equations and electromagnetic waves explain why a should be identified with the speed of light? *Note: I'm not sure if it's appropriate to attach someone else's pdf to posts, so I didn't do so. (This is my first posting here so still trying to figure out the rules.) If someone can kindly inform me on if it is/is not proprer to do so, that would be appreciated. I'll happily post the pdf if it is allowed.  http://www2.physics.umd.edu/~yakovenk/teaching/Lorentz.pdf