Match Definition and 122 Threads

I saw a YouTube video where someone took nichrome wire and a high voltage source and managed to light a whole series of matches. I got me curious so I ran some numbers on how much wattage could be produced for a given length of nichrome wire and a given voltage. And assuming time is no issues...

So i saw a trick the other day where you place a coin under a match, and that match is leaning against another match that is standing upright, if you light the center of the leaning match on fire then it will start to float and you can remove the coin, what i am asking is how this works. Here...

I have a shoe box full of old match books from bars and casinos etc. I store them in a closet. It just dawned on my that it might not be an ideal storing situation. Is there any danger them like this? Should I put them in a metal box and in a garage? Could them spontaneously light and burn my...

I've been observing cars RPM and noticed that automatic transmission American cars reach 60 mph at 2250 RPM while automatic transmission Japanese cars reach 60mph at 2500RPM. Why is that? Like, what determines RPMs? The rotation from what is being measured?

For example, if you have the function f(x) = x2 then find: d/dx any number3x∫ t2dt Why must the dx in d/dx ∫f(t)dt always match the upper limit in order to compute the integral? Why is the lower limit of no concern? I know that you must take chain rule into consideration and change 3x to...

Homework Statement I was wondering whether striking a match is endothermic or exothermic. Homework EquationsThe Attempt at a Solution This seems quite straight forward as striking a match releases heat, which is obviously exothermic. However, the process of igniting the match requires heat...

If I had a grey pair of sneakers so they generally can go with say khaki pants. So what colors can my shirt be? Gimme your fashion advice haha

I'm just curious, but when will I know that it's not just carelessness that is causing me not to be able to do the problems?

Homework Statement Evaluate using the Squeeze Theorem. \lim_{x\rightarrow0} (2^{x} - 1) cos\frac{1}{x} Homework Equations The Attempt at a Solution -1 ≤ cos\frac{1}{x} ≤ 1 \\ 1 - 2^{x} ≤ (2^{x} -1)cos\frac{1}{x} ≤ 2^{x} - 1 \\ 0 ≤ (2^{x} -1)cos\frac{1}{x} ≤ 0 \\ ∴ \lim_{x\rightarrow0}...

I understand that too long of a time scale won't resolve an event clearly, and too much has the risk of exciting whatever you're trying to measure. Is there some sort of resonant effect when you match, say, a radiation frequency to the time of an event taking place? Specifically I'm applying...

Why should the input follow the exact output in control systems (Transfer function). What if my system is an amplifier ? shouldn't that means that the output is the input * gain ? I can't understand the differences between dealing with a real system ( such as an amplifier) of dealing with a...

I've come across a bug in a program that calculates rankings from the results of a bridge tournament. It should be fixable by increasing the precision, but it's not obvious what the precision needs to be. (I don't have access to the source and anticipate push back from the coder, so I need it...

Homework Statement Which of the following direction fields corresponds to the equation: y' = y-t I have attached an image of the direction fields Homework Equations The Attempt at a Solution I get that each arrow represents the slope of the function at that point, but I'm...

A panel put out over 30.7 volts, say 34 volts and I have a micro-inverter that require a voltage of 11-30 to work. Other than shading some of the panel, is there a way to half the voltage from the panel without as much loss from shading some of the cells to work the inverter?

I have been trying to understand polarization match in the text from Balanis. The first attachment is the text scanned from the text explaining the polarization of an antenna in RECEIVING mode. I try to understand what the book said and I came up with my interpretation in my writing and drawings...

Hello This is my first post here. Although I've often read posts in Physics Forums, I've never actually contributed anything - so here goes! I always enjoy a good hand-waving argument on orders of magnitude; when I first started my astrophysics degree, one homework question was "estimate...

Homework Statement Imagine that a block of mass m2 is on top of block m1, which is on top a horizontal floor. m1>m2. A force F is applied to block 1 to the right. Both block1 and block2 are connected to the same pulley. In other words, one end of the pulley is connected to block1, and the...

John has been accused of murder and the police have found DNA evidence at the scene. The probability of a DNA match given that a person is innocent is 1/100,000. The probability of a DNA match given that a person is guilty is 1. John lives in a city where there are 100,000 people who could have...

Calculating "match" between two data sets Hey guys, I'm developing a program for comparing the effects of various terms in a Monte Carlo experiment. Right now I have it so you can visually see the effect of "switching" terms on and off and need a way of quantifying how much two lines "match"...

I ran into a kind of strange thing today while coding. I needed Pi in a program, so I used 2*accos(0.0) to pull it out, but my answers were slightly off. I checked the Pi calculated and it was off after a few decimal places. "Odd", I thought, and just decided to put in Pi as an assigned number...

https://www.youtube.com/watch?v=S02HkP13ijA Cat that became Premier League star is homeless tabby named 'Kenny' This feline has interrupted Liverpool vs. Tottenham match and captured everyone's attention for 1 minutes before being picked up by steward. I guess it wanted to kick the ball.

Homework Statement Homework Equations moment = force x distanceThe Attempt at a Solution on sheet. According to the book, the max moment is 5.6 kN (at a distance of 2.4 m from point A), which was my calculation before adding the force at A (.8 kN upward) whats wrong?

Homework Statement To evaluate the following line integral where the curve C is given by the boundary of the square 0 < x < 2 and 0 < y < 2 (In the anti clockwise sense): \oint (x+y)^2 dx + (x-y)^2 dy The Attempt at a Solution Firstly it is noted that for a square ABDE : Between...

I was integrating and I noticed that if I integrate one way I get a diff answer than if I integrated another way... My work is in the paint document. I followed all the correct algebraic prodedures I believe... but anyways which one is incorrect?

Hi. The grating equation says n x λ = d sinθ. Where d = 1/N (the nymber of slits per unit length.) Using the equation and solving for a grating with large number of slits gives the result that the diffraction pattern should have a greater angle of deviation from central maximum for...

Hi I'm wondering if someone could help me out finding the Q-value fom a beta minus decay. It's a 90Y → 90Zr + e All sources I have says that the energy released is 2,28 MeV, but when i calculate i get 1,78 MeV So far, I've looked up the mass of the 90Y and the Zr90 and the electron...

Homework Statement Twins are separated at birth on earth. Twin B travels in a straight line back and forth at a velocity, V. According to twin A, who stays on earth, twin B travels away for 10 years, and then back toward Earth for ten years. They send light signals to each other at...

Homework Statement This is for a class to learn about making order of magnitude estimates. I want to estimate the amount of energy released by burning a match. Googling gives an answer of about 1BTU (just over 1kJ) but I can't think how to estimate it from general knowledge. Homework...

Homework Statement PROBLEM: Match the inequalities with the corresponding statements. INEQUALITIES: 1) |a-5|< 1/3 2) |a- 1/3|< 5 STATEMENTS: a) The distance from a to 5 is less than 1/3 b) a is less than 5 units from 1/3 The Attempt at a...

Hi! I started to look into freq response analysis of a cantilever beam using COMSOL. Luckily COMSOL already has an example model "Model Library>> Structural mechanics module>>Dynamics and Vibrations>>rotating blade". While not changing anything in the model and with Omega=0 and Cloris =0, I get...

Dear Members I would like to match numbers in two files of extensions .lw & .pw and put the results according to matching numbers. For example, the .lw file contains data as 59880 SPC X2d12G 4714 UNK X 900B and .pw file has 59474 SPC X2c8bG 991 ILE A 118B 59726 SPC X2cdfG 1803 SER A 168B...

Keyboard input does not match keys - Please help! I currently am having a massive issue with my computer. The input keys do not match the keys on the keyboard and all input goes to hotkeys. I have to use on screen keyboard to type. The keys themselves worked, but are automatically redirected...

Hey guys, this is just a problem I have been playing around with in my spare time, but it occurs to me that someone might have been working on this before. So I figured I'd ask the wonderful people here for help. The problem is: Assume that the probability of player A winning a point is p and...

Homework Statement A player stands with his feet at the point O and serves the ball from a point Y at a height of 2.4000m vertically above O. Assume that the ball then travels in a straight line directly over the net at the midpoint A, which is at a height of 0.9144 m, before bouncing at...

Mathcad help: "The forms of these values must match" error Homework Statement I am getting an error, when I assign a value to 'num', stating: The forms of these values must match This value has the form: Unitless, but others have the form: f(any1, [unitless]) => [unitless] I cannot...

I've picked up a 13.56 MHz RF generator from eBay which I plan to use for an ICP plasma project (this is what it was designed for). I need to construct an RF coil and parallel capacitor with a resonant frequency of 13.56 MHz but I also need to construct an AMU as, as I understand it, as soon...

Why the values of inductance for an air-cored coil are not exactly the same for changing current across it in practice??

Hi Please look at this link. It is only very brief. It describes how to extract iron from iron oxide on a match head. My questions are: where does the carbon come from in this equation Iron(III) oxide + carbon → iron + carbon dioxide 2Fe2O3(s) + 3C(s) → 4Fe(s) + 3CO2(g) Is it...

I try many time to model a simple tensile test for steel MAT_024 but the graph doesn't match from Dyna result and Test result. Process: 1. Collect data Tensile strain and stress convert to True stress and strain use formula True stress: eng. stress*(1+eng. strain). True strain= ln(1+eng. strain)...

A first-round match at Wimbledon has gone to 59-59 in the fifth set. They started playing yesterday, got suspended because of darkness, resumed today and got suspended because of darkness again. They've been at it for ten hours so far...

"Calculus" (Larson, et al) 9th ed: p. 169 #29: No match to answer key. Homework Statement Locate the abs extrema on the interval of the function: y=t-|t-3| for interval [-1,5] Homework Equations |x|=\sqrt{x^{2}} The Attempt at a Solution I thought this would essentially be a...

Hello I am appealing to the computer savvy bunch here and asking for a graph. I need the graph to show a function that is of the form (Acos(x)+Bsin(X)) it can be simple... just anything harmonic I dont' even need the function you can just draw it. and then I need a polynomial that has the...

I have a question about impedance matching with transformers. If I have a source impedance of 20 K ohms, to step up the voltage does the primary have to match 20K ohms with a secondary of 40K ohms for a step up of 1:2. Or can I change it so the primary is 50 Ohms with a secondary of 40K ohms...

Homework Statement Nuclear energy changes are significantly greater than chemical changes. The detonation of 1.00 g of the explosive trinitrotoluene (TNT) releases 2.760 kJ. How many grams of TNT would be needed to match the energy released by one gram of U-235? ( 1 gram of U-235 contains...

Hello, One topic I would like to discuss here is the comparison of our understanding and knowledge of the cosmos, matter, energy, evolution and the existence in general WITH that of the other "civilizations" if they exist elsewhere in the cosmos. I am just curious...if someday we visited...

Homework Statement Find the mass of a single match. You are only allowed to use the following things: a ruler which weighs 10 gramms, and a matchbox full of matches. The Attempt at a Solution Well I haven't tried anything yet since its kind of hard to get this thing rolling. But since...

Hi, I'm trying to work this problem out and unfortunately my book doesn't have an explanation. Homework Statement A match head is rubbed a distance d over a rough surface in order to increase the temperature to its flash point. If the patch head material has a mass m and a specific heat...

I've watched some 2009 lectures by both Susskind and Krauss, and it sounds like they're telling different stories. Krauss seems to be saying that the origin of the universe is a plain-jane quantum fluctuation, but Susskind seems to be saying that at one point all matter in the universe was on...

What do the phenomenologists of unified theories (strings, loops etc) try to match at lower energies when there are so many conflicting theories lying around at these energies? I understand that certain things should be there in any model - like chiral matter, three generations etc - but a lot...

Just watched the movie Avatar. Can we light up a match (or produce fire) where there's low/effectively no oxygen in the atmosphere e.g. moon? If not, can a spark still be produced? Thanks!