Concepts Definition and 412 Threads

Homework Statement A series of true/false questions. I guess I don't understand the concepts of this very well: 1. If you know the directional derivative of f(x,y) in two different directions at a point P, we can find the derivative with respect to the x and y axes and thus we can...

Role of Concepts in describing observations of concrete objects The important thing about Isaac Newton's Laws is not the statement but the abstract concepts he invented, like the concept of Force. Force is not an observable, concrete thing. It is an abstract idea that helps us to...

I don't understand how matter can be transformed to light and light can be transformed into matter? Also, how exactly does this happen when something happens to one particle and something equivalent happens to another particle of the same type on the other end of the Earth instantaneously...

Hey everyone 1st off this post will contain a few ideas that aren't really all that related to each other but I’m posting them together not to spam the boards. I posted them under General because the topics are literally all over the place Could it be possible that dark matter was left over...

Homework Statement I have an oratorical exam, with two of these statements given randomly. So I have to give at least 5 minutes of elaboration of each statement. 1. A force is something capable of changing an object’s state of motion. To produce a change in motion, there must be a net or...

Homework Statement Three forces act simultaneously on a 2.70-kg block. For clarity the drawings show the forces separately. The block starts from rest and, as a result of the combined action of the forces, undergoes a displacement s, which has a magnitude of 6.50 m. What is the final speed...

I have written this to test my understanding of some of the concepts involved with Special Relativity. Any comments, corrections; agreement or disagreement; will be gratefully received: 1.Every IFoR can be considered to be stationary. An observer positioned within one would certainly say that...

Homework Statement 1. What type of energy is involved in weighing something on a spring scale? 2. What type of energy is involved in winding a watch? 3. Is a machine's efficiency increased if the work done against the resistance force is decreased or if you decrease the work against...

initally there's a electric field pointing to the right near a rod...something happens and the rod becomes negative on leftside on postive on rightside whihc supposedly generate another electric field near the rod..does this new one oppose the other one in terms of direction or make it stronger?

I know these aren't exactly physics problems but I'm being asked them in physics so... Homework Statement 1) As lead melts there is a change in it's... Temperature Heat of fusion (what I now think it is) Avg molecular KE (what I thought it was) Avg molecular PE 2)In a room there is...

Hello, I am doing a PhD in computer science (on simulation and modeling) and my research is based on the work of a few physicists. I have written around 10 papers (journal, IEEE and other international conferences and local ones) on this topic. I normally add a contribution (let's say 4-5...

Hello, I have a few questions that I have made myself, but I don't know how to answer them. 1) Say that there is an isosceles triangle ABC. Two of the equal angles are 1/∞. What is the other angle? 2) Is a sphere really a sphere if you can draw a tangent to it? 3) Assume that there...

Homework Statement so i just had some questions: 1. is there a difference between h and d? sometimes i see P = \rhogh and other times P = \rhogd is there a difference? because if d=depth while h=height, would d always be a neg number? 2. for hydrostatic pressure, i was taught: P = Patm...

Well, I'm trying to grasp the concepts behind the following problem : "A guy puts some air in a vassel, the air's temperature was t0 the vessel's basis area is 50 cm³ and the height is 20. Afterwards the vassel was set onto a container full of water at 300k (Similar to Torricelli...

Although I haven't been too much into math in the past, with the exception of statistics being a college minor, all of a sudden I have an interest in coming up with mathematical equations to describe/predict how certain things work. I want to take data sets and come up with equations to...

I have posted a similar problem not long ago.This time, I am trying to find a connection between 3 concepts that would possibly lead to the answer to the problem. I have heard that there is a way to find the probability of getting a particular sum by rolling multiple six-sided dice at the...

Homework Statement f(a) > c > f(b) A = { x : b > x > y > a implies f(a) > f(y) } let u = sup(A) show that f(u) = c Homework Equations I have no idea in particular, save for the definition of the supremum: \forall x \in A x \le u if v is an upper bound of A, then u \le v...

I'm a 3rd year physics major and my friend is a 3rd year computer science major, and for a bit of fun we want to do some sort of project that will utilize both of our skills. Some sort of computational physics problem seems appropriate, but with my limited knowledge, it seems that a lot of them...

iam confused so much about some concepts of turbomachinery. according to the classification of rotodynamics devices there are 3 types radial flow,axial flow and mixed flow and axial flow gives higher flow rate compared to radial flow and lower head. so my question is what is meant that axial...

Often time we hear people who are good at math understand the concepts behind it.. What do they mean by concepts behind it? Proofs? I always imagined a person good at math could do the math but also had the capacity to apply many areas of math to a single problem. Like for instance..when...

Hi. I have high functioning autism and like many other people on the spectrum I think predominantly in pictures and that's how I learn scientific concepts. Every concept I learn I represent it with a picture. Unfortunately a lot of the books on chemistry in particular (physics and biology I have...

Homework Statement The pressure at 10 m below the surface of the ocean is about 2.00×10^5 Pa. Which of the following statements is true? a. The weight of a column of seawater 1 m^2 in cross section and 10 m high is about 2.00×10^5 N. b. The weight of a column of seawater 1 m^2 in cross...

Hi, I'm very ashamed about getting a fully understanding of these vector product concepts. But i did a lot of search and get an idea about them. I read Feynman's lecture on physics and almost completely understand the mathematics behind their properties. In that book feynman proves that cross...

I should probably start by saying that I'm not too interested in the mathematics yet, I'm after conceptual understanding. I'll get the maths easy when I've got the concepts. ok, this is what I've got so far, stop me when i get it wrong... the black lines represent the inertial coordinate...

I need a statistics book to help me understand concepts like skewness and kurtosis. I don't need a really advanced book, just one that will hopefully give me an understanding about the topics and make me able to implement them on my own. I have very little background statistics or probability...

I have a Q&M final coming up. The math I can do. However I would like to strengthen the concepts. Can anyone point to a resource that includes conceptual test? This is for junior level Q&M. Thanks

1. I'm having a final this week and I wanted to review some of the physics concepts, but I don't understand what the book is saying so I'm wondering if anyone can give me a site that is easy and understandable for me. (or you can write it down here) I mostly need to know the concepts on light...

I've been doing quite a bit of reading on the Klein Paradox, though I have to admit a lot of the math goes over my head. So I was hoping you guys at PF could clarify a few things and help me check my conceptual understanding so far. I found this post...

Was in the shower and I was thinking of this conversation I was having. They were completely ignorant to things as they really are. Instead they took them as how they THINK they are. i.e. science. I assume he does this so that the concepts can fit to whatever he is arguing for or so that he...

I've been studying for our final exam throughout this weekend, and I realized that there is a lot that I don't remember. So, instead of asking each individual question, I'm going to try to ask one from each concept that I don't understand. Quite a few of them I have absolutely no idea how to...

Hi, I have 2 extremely hard questions. Any help would be appreciated so much! :) 1. Starting from a speed of 0 m/s, a proton is accelerated through a potential difference of 32000 V. What is the proton's velocity? 2. Is there a formula that I should use to solve for this problem? 3...

A wire and a battery (a AA Duracell battery just to keep things clear) are connected in series. The way I understand it, the wire (say, 1 meter in length) already has its fixed number of charges, both positive and negative. When those charges move, meaning when there is a potential...

I'm writing a paper on the magnetron, and was wondering if anyone can help me with some conceptual elements of its workings. I understand it is a thermionic diode, and that a parallel magnetic field causes emitted electrons to travel in a circular path about the cathode. How is it that...

Homework Statement TRUE or FALSE for each statement: *Only very small objects have a wave function. *Electrons show interference effects like waves. *The wave function times the volume gives a measure of the probability of finding a particle in a particular region. *The absolute value of...

Homework Statement Hi I need some concepts on magnetic fields explained to me. 1.) I know in theory that if you have a current carrying conductor say along the X-axis then the magnetic field generated would be in the y,z components So let's say I wish to measure the magnetic field in real...

Homework Statement Give reasons why you regard each of the following statements as true or false. Include appropriate equations and explanations using underlying basic physics concepts and laws. a) The condition for uniform circular motion of any object is that its velocity and speed must be...

I'm going to be taking a precalculus course in the fall. I'd like to be as prepared as possible for it so that I will be able to get as much out of the class as possible. I have access to a variety of textbooks, some are rather rigourous Precalc texts from the 60s and some are the "modern"...

I am not sure about these things about vector: - Is it true to say that a vector n orthogonal to vector n1 and n2 is the cross product of n1 and n2 ? - Is it true to say that if a line is parallel to a plane, the normal vector of the plane is orthogonal to the parallel vector of the line ...

Now as I understand, a force must be present to cause centripetal acceleration. So as a car goes around a circular arc it is friction between the tires which causes centripetal acceleration. So since the car is turning around the curve the friction will be perpendicular to the instantaneous...

You need to deliver a package of mass M from your current location (x = 0) to a room at the end of the hall (x = D). You have an amount of time T in which to do it. Neglecting resistive forces, what is the minimum amount of energy required to accomplish this task? NOTE: You expend energy to...

I am extremely interested in what I assume would be called particle physics. I want to learn all about basically elementary particles and their interactions, however in my high school physics course thus far we have only really gone over simple vectors and such. We aren't even learning about...

Take a look at this: http://www.gadgetsquick.co.uk/product_thumb.php?img=images/powerball-neon-blue-litup.jpg&w=214&h=200 I am looking for ideas about a physics project. The theme is "future household energy concepts". I found this thing from a http://www.gadgetsquick.co.uk website. How...

Dear All, I have learned the Uniqueness and Existence theorem in last lecture, however, the instructor told us that the proof is omitted because it is beyond scope of the course. I am more concerned with the derivation of the Uniqueness theorem now. I need some clarification here...

I need some help on those multiple choice questions that I'm using to learn the concepts. Some of them I know how to do and needs someone to check my work. Other ones I need hints so I know how to start. 1. Three ½ μF capacitors are connected in series as shown in the diagram above. The...

Trying to get my head around some basic exterior calculus concepts So #1 - 1-form or covector the grad is a covector / 1-form defined as something that combined with a vector takes it to a scalar, for example divergence is a scalar which is the dot-product of a function with its grad (e.g...

All throughout high school I was able to memorize the most important concepts and that would be enough to produce great test results. I am now in my second semester of college and the questions posed by the professor are more thought provoking and require much more knowledge ABOUT the main...

In another thread Naty1 said: The Wikipedia pages on http://en.wikipedia.org/wiki/Four-vector" ) are not wonderful, but they are a good starting point. I don't know exactly how far your background in these concepts extends, so I apologize if I go over stuff you already know. Basically...

Hi, Could you explain me a few things I still don't get about special relativity ? I've been tought a few years ago that special relativity wasn't good for handling accelerations... well I've been reading books and a few topics here, and I'm now convinced it is not true... for exactly the...

Hello all, I have come across some questions in thermal engg., of which i have answers also as per the book where i have found the questions but unable the find the concepts and logic behind them to solve the questions. kindly help me to find the solution with the logic also. following are the...

Homework Statement A magnetic tape is being played on a cassette deck The tension in the tape applies a torque to the supply reel. Assuming the tension remains constant during playback,discuss how this torque varies as the reel becomes empty. Homework Equations The Attempt at a...