Beginner — 350 discussions

hey guys~I am new here. Recently I am planning learning the knowlodge about computer security (basically anti-hacker staffs) However, I am quite confused about where to start my learning. I am graduated mechanical engineering student which means my computer science knowlodge is quite...

Below is a sample code. My professor starts code and we have to finish the code. Below is not the assignment but a sample I have written up to help my question. I have two .cpp files one named main the other named func1. Within func1 I have a function called matheq. I was just wondering if there...

Homework Statement Two train cars are on a straight, horizontal track. One car starts at rest and is put in motion with a constant acceleration of 2.4 m/s2. This car moves toward a second car that is 29 m away and moving at a constant speed of 4.0 m/s. a.) where will they collide b.)...

Hey there, I have currently set a goal to become a self taught physicist. I recently joined this lovely forum in order to inherit some good information and materials to work with. What I currently need is an awesome book for learning the basics in physics specifically for someone like me also...

I'm a freshman in high school and was thinking of buying a beginner pair of binoculars. Could someone suggest one I might buy?

Hi, I stumbled on your website when looking for a good place to ask educated professionals. I'm 16, I have a question on evolution. Ok so let's say there are these birds on an island with a food source that require long pecks, but these birds have smaller pecks than needed. So after a...

I'm basically through with the AP Calculus BC curriculum, and I think I have a good grasp on calculus as a set of tools. However, I don't think I've got a great grasp on calculus as a concept [we haven't done any proofs this year and I know very very little about Delta-Epsilon proofs.] I was...

Hi all, I'm a beginner in FEA and got a problem regarding nodes. Can you split a line into a number of nodes using APDL script? Then a force should be applied as these nodes using F. The line is and arc. Thanks in advance Chri

So, I want to build a timer in the style of an old-school flip clock (like this http://www.ladidah.com.au/range/images/flip-clock-grey.jpg) that counts from 000:00 minutes to 108:00 minutes. Whenever a user enters a certain sequence of numbers on the computer, the timer should reset itself to...

dear all, i am MATLAB new user and i have some problems about it. I generated a code as below: function data = findtext(redc,greenc,bluec) txt=0; if bitand(redc,4)== 4 txt=bitor(txt,128); end if bitand(redc,2)== 2 txt=bitor(txt,64); end if bitand(redc,1)== 1 txt=bitor(txt,32)...

I want to buy a robotics kit for something to do over the summer. Virtually all of the posters in this thread endorse the Lego Mindstorms NXT set, but the OP in that thread was specifically asking for a robotics kit for a five year old. However, I am impressed with the kit from what I could...

Homework Statement A proton, which is the nucleus of a hydrogen atom, can be modeled as a sphere with a diameter of 2.4 fm and a mass of 1.67 multiplied by 10-27 kg. Determine the density of the proton. Homework Equations Volume=(4/3)pi*r^3 Density=mass/Volume The Attempt at a...

Greetings. I'm new to COMSOL and am in the stage where I know what I want done, but I just can't get the software to do it. Suppose I model out a metal spring, and fix one end of it in place. I want to pull on the other end, and then plot some value relevant to the deformation of the...

Homework Statement a particle is described by the normalized wave function \psi(x,y,z) = Axe^{-\alpha x^2}e^{-\beta y^2}e^{-\gamma z^2} Where all constants are positive and real. The probability that the particle will be found in the infinitesimal volume dxdydz centered at point...

Homework Statement you want to prepare 500 ml of 1 M KNO3 at 20 C, but your lab and water are 24 C. How many grams of solid KNO3 (density= 2.109 g/ml) should be dissolved in a volume of 500 ml at 24 C so that the concentration will be 1 M at 20 C? what apparent mass of KNO3 weighed in air is...

The problem is as follows: Assume interest in your savings account is compiunded continuously at a rate of .25%. Then the rate of growth of savings is proportional to its size with the proportionality constant k = .0025 Write the differential equation that models this situation. Let M be the...

Homework Statement I am trying to find prime numbers that are i,i+2,i+6,i+8 apart. Could someone tell me the last set that this gives? Homework Equations - The Attempt at a Solution program sieve_t implicit none integer*1 s(1000000), offset (10), sequence integer i, j, n...

Okay, so I'm learning some basic index notation, and I have a few questions... Homework Statement f= scalar field F = vector field so, we are supposed to show that curl(fF) = fcurl(F) + (\nablaf) x F The Attempt at a Solution curl(fF) = [\nabla x (fF))]_{k} =...

"ionising radiation such as \alpha and \beta particles and \gamma rays" is what i have typed (without quotation marks). But when I build it the pdf output is wrong: it does put in the correct symbols, but it leaves no spaces at all from after the word "as" and puts everything after "as" in...

Any help is greatly appreciated Homework Statement I am trying to sort a string of vectors in the proper order. My problem does not involve theory, it involves syntax errors. Moving from Java to C++ is sure a pain.. I have 2 c++ files, sorting.h and sorting.cpp I keep getting this error...

[SIZE="3"][FONT="Times New Roman"]I am looking to start learning programming more or less on my own. I can make some advanced programs on the TI-83+ calculator and have been for the past year. I learned just from reading the manual and messing with the different logic operators and commands...

hello everyBody.. am a beginner in MATLAB i need lil help in the equation blew.. and if anyone has any tutorial for MATLAB i'll b more than welcome to accept them :P y=e^x . cos x plot : pi greater than x greater than 0 then plot : -pi smaller than x smaller than one then combine...

need urgent help I'm a beginner using matlab, I saw this function working: function une=coloca(u) num=1:256; val=288-(u*3000); une(1,:)=val; une(2,:)=num; but when I try to use it, this error appears: ? Input argument "u" is undefined. Error in ==> une at 3 val=288-(u*3000); What could be...

Define "variation" to a beginner How do you define the word "variation" "variability" to a complete beginner, like myself. For Example, I understand 'R' explains how strong the linear relationship between the change in X and Y. But sometimes, let's Say R=.91, people will say the linear trend...

[SIZE="3"]Problem 1 Just starting on the Current & Power chapter and I'm a little confused. I know they're just basic definitions and concepts, but I'm having trouble wrapping my head around it. Easy questions follow, but I'm lost. Homework Statement How many electrons flow past a...

Stopping Distance + Reaction Time Problem ---> Physics beginner Homework Statement A car is traveling at 80km/h, and brakes with a reaction time of .5 seconds. The car decelerates at 8m/s/s, determine the stopping distance of the car. Homework Equations - V1 = V0 + at - D = V0t +...

Hi, I'm new to the subject and I've been trying to catch up quickly, but something that's been bothering me is why exactly do Microwaves heat waters, fats, etc., even though things with a similar frequency and wavelength(Radio waves, Infared) do not, or at least as quickly?

Hello, I am a high school physics enthusiast (classical mechanics, electricity and magnetism, relativity, astrophysics, cosmology, quantum mechanics, particle physics, anything about light and gravity etc) but I'm just a beginner, and I would like to learn more about the above mentioned...

Beginner "Triangle" Problem Homework Statement A ladder 4m long rests against a vertical wall. If the bottom of the ladder slides away from the wall at a speed of 30cm/s, how quickly is the top of the ladder sliding down the wall when the bottom of the ladder is 2m away from the wall...

So I've been reading Brian Greene's The Elegant Universe, and I'm not quite sure I understand general relativity. This is the way it was roughly presented in the book. Two friends are throwing a baseball back and forth at 20 m/s. However, when one of the friends begins to run away from the...

Im a begginer at Matlab and have a simple question. I have a equation with lots of variables that can be easily entered incorrectly. Therfore i was going to split up the term. For example if i have y = x^(6Z+2) i was going to put the m file as y=x^u u = 6Z + 2 then z = 3 for...

in MATLAB how do i make a variable which is dependent on another variable, for example y=2*a+3 for any a, so that when i change a, y will automatically change i have only managed to set a value for a, then set y and i get a fixed value for y

Homework Statement A dynamics cart with a mass of 2.2kg is moving at 33 cm/s to the right when it has a head-on collision with a second cart with a mass of 1.2kg moving in the opposite direction also at 33 cm/s. After the nearly elastic collision the first cart continues forward at 13 cm/s...

Homework Statement A rigid, perfectly insulated container has a membrane dividing its volume in half. One side contains a gas at an absolute temperature To and pressure Po, while the other half is completely empty. Suddenly a small hole develops in the membrane, allowing the gas to leak out...

I am a filmmaker, and I have some questions about wave functions. I have read as much in English as possible (as opposed to math language) but unfortunately, I haven't dedicated my life to mathematics and understand math languages, so I suppose I'm asking for an explanation in English. I had...

Hey i am new to computer science have just started taking C classes,i got an assignment its really hard below is the question,and below that i have posted my answer what ever i have done up till now,can somebody help me fix the error and i haven't done function 3 and 5 if somebody could help me...

Hey, I want to get into robotics but I don't know where to start. Is there a book I should buy or some kits that i should start with that aren't too expensive. If there are any suggestions on how I could turn this into my hobby please post :)

hello everyone, i'd be really appreciative of some help. I'm doing as physics and have never done proper physics before therefore I'm finding it quite hard. we are doing about waves at the moment and was wondering about a couple of things:- 1st - how to calculate frequency using the time base...

hello everyone, i'd be really appreciative of some help. I'm doing as physics and have never done proper physics before therefore I'm finding it quite hard. we are doing about waves at the moment and was wondering about a couple of things:- 1st - how to calculate frequency using the time base...

Homework Statement a motorist is driving at 20m/s when she sees that a traffic light 200m ahead had just turned red. she knows that this light stays red for 15s, and she wants to reach the light just as it turns green again. it takes her 1.0s to stop on the brakes and begin slowing. what is...

Okay, this is the question that i need to solve using mathematica: Define the function f(n) which counts the number of zeros in n if n is the integer greater than 0. If you input 105, 1005, 10005, find f(n). I want to use Module in this question and I just found out that i have to use...

Hi All. I am trying to rewrite a program that i have in MATLAB to one in fortran. as i chug along, i am comparing the results and i am getting funny answers. This is the program in have in fortran so far: ccccccccccccccccccccccccccccccccccccccccccccccccc program main implicit...

Hi All I am new to fortran and there are things that I believe fortran should do and don't know how to do it - I am using fortran 77. 1- I know how to declare variables, but i do not know how to make sure that i start out with zeros and not use old data that might have been stored by a...

Hello everyone, I am having problems with these 2 drawings. Basically, I am suppose to draw the 3D (isometric) view of the diagrams. The diagrams both provide a front and right-side view but I cannot seem to picture the object and don't know where to start. Please help...

Hi! Can someone give me a general idea of how I do this? In my lab today we a pulley system with two spring balances attached to a long sting. We had to do several configurations and measure the angle and record the reading on the spring balances. Could someone guide me as to how to do the...

Hi all, 2 questions here 1) I've been doing some questions on laplace transforms and have been running into some trouble getting my answers into the same form as the answers given with the questions. For example: f(t) = 1 - e^(-t) Using the linearity property i got 1/s - 1/(s-1) which is...

I'm trying to understand what Braket state vectors are... and I'm not sure if I completely understand what's going on. Could someone clear this up? Here's what I (think) I understand now. A ket is pretty much a state vector (written with different notation). A state vector is pretty much a...

1. A poster advertising a student election candidate is too large according to the election rules. The candidate is told she must reduce the length and width of the poster by 15.0%. By what percentage will the area of the poster be reduced? Im not sure how to go about this problem. I am just...

[SOLVED] Very beginner physics 1D motion question! Homework Statement Two cars move in opposite directions toward each other on a level, straight, one-lane road. When both drivers begin to brake, their front bumpers are 275 meters apart. The smaller car is initially moving at 25.0 m/s and the...

Im learning to play the guitar, have a really nice sounding spanish acoustic guitar by gb&a. I can play chords pretty well, and play some leads too, but I don't know what songs to move on to. I've been able to play dance of death (a little slow on the leads), stairway to heaven, wish you were...