Practical Definition and 308 Threads

my doubt is that let's say we have a ratio 5:10 now the equivalent ratio for this would be 1:2 but what I am not able to understand is - let's say we have a situation in which it is given that the ratio of girls to boys is 5:10 which means for every 5 girls we have 10 boys but if we see the...

Say I have a real counter flow heat exchanger using air and water. I run a test so I know every parameter; mass flow rate of both fluids, surface area, and in and out temps. This is great. Now I can calculate the heat transfer rate, my log mean temperature difference, and overall heat...

What i mean if we change state/spin at one end it will immediately effect the other. Can we see that live using two camera which may be 10 meter apart so that minium time delay. Is there any video proof exist such kind?

If a country's GDP is 200000,0000000 USD (too many zeros eh?), and $$ \text{GDP} = \text{ Compensation to employees} + \text{Government Spendings} + \text{ Investments} $$ (Closed Economy, for simplicity, I mean for my simplicity not the country's) Why do they call it Compensation to...

In another thread, @Grinkle asked about a solar fridge project. In the end, he decided against it, but it set me to wondering if it could be done for people living off grid. At this point, I really miss our beloved Jim Hardy. Jim would have brainstormed with me, then he might have gone in...

I have been learning gr on YouTube for the last few months. Most of the videos and the book I have focus on high level understanding. I can do all of the tensor calculus proofs. However simple questions like how you set up a velocity vector or measure proper time in schwarzschild are beyond me...

What with copper becoming more and more valuable, and metals used in coins being a non-renewable resource, might it not be practical to mint ceramic coins that contain microdots that would make the coins difficult to counterfeit? Microdots are already being used, for example, in car paint as...

I was enjoying my (very short) hot shower this morning and realized that the lovely warm water was flowing over my body (sorry - too much information) only once and then disappearing down the drain. This water - and what comes out of the washing machine, dishwasher etc. could be at a seriously...

This is regarding the positive feedback of an Op-Amp and the inverting Schmitt trigger. This is a typical inverting Schmitt trigger - I need to design the Schmitt trigger such that I have a threshold voltage of around 2V, when my ##+-V_{CC} = 8V##. The slew rate of the Op-Amp allows for a...

Recently I asked if prime editing can be used to reverse the random mutations we accumulate with aging(https://www.physicsforums.com/threads/can-prime-editing-fix-every-harmful-mutation-in-all-our-cells.1003279/) but now I have a different question. Can we simply replace our genes to get rid of...

Hello, I need to scale down a human model by 1:20 i.e, i need a human model of 9 cm height scaled down. Help me calculate the weight of the 9 cm scaled down human model. Regards, Viky

Hi everyone, I was quite excellent at STEM subjects at school, but struggled (bad) at art classes. Here's why: At grade 9 of middle school, one of the job (assignment) that I had to perform in weeks was singing Amayadori by Mayumi Itsuwa. I and other students were given photocopies of music...

I was trying to look for something that works a lot of examples of integrals over surfaces, volumes etc. in general relativity. Tong's notes and some others are good on the abstract/theoretical side but it'd really be better at this stage to get some practice with concrete examples in order to...

Hi, In high school physics I learned how to convert between Celcius, Fahrenheit, Kelvin, and Reaumur scale of temperature. While the first three scales are highly used, why do we learn the fourth scale (Reaumur) when there aren't any practical use of it? Just for formality? Bagas

Hello! Can someone point me towards some good books about laser from a practical/experimental perspective (maybe even a review paper). Most books I found spend a lot of time going through derivations and theoretical concepts. I would like to go deeper into that, too, at a point, but for now I...

https://www.physicsforums.com/attachments/273785 What are the possible materials (beams, H-profiles) etc that can be used to withstand the pressure of the whole system if there are 12 tonnes of wheat in the pipe at all times? How you would make this system work? There always has to be an angle...

Recently I started wondering why there seems to be so few practical/engineering applications where you need to calculate the momentum of something. I must emphasize that I don't mean usage of the concept of momentum or the law of conservation of momentum, but the value of the quantity itself...

Hi All, I understand carbon sequestration in the simplest sense is capturing and storing carbon. As seen in the title, I'm going to split this into two sections. i) How does it work? I imagine that trees, in a sense are doing this. They take in the carbon from our atmosphere and is stored...

Hello, I think I understand how Bernoulli equations works but I am clearly uncertain on some aspects of its application. For example, let's look at the figure below: 1) The static pressure is ##60## ##psi## from the city water supply. There is not flow (tap closed) so the pressure at the...

Summary: I set it up my investigation as in the image with two independent variables: the mass of ball 1 and the angle of ramp inclination. I released ball 1 and started a timer when it stuck ball 2 then stopped it at the end of the track. I then took the average velocity of ball 2 over the 1...

Homework Statement: Carry out an investigation into the relationship between the mass of an object (m) and the distance from the fulcrum (d) at which it will cause the plank to tip. Homework Equations: You will use a ruler to model the plank and a pile of quarters (6) to model the mass of the...

what is the practical application of engineering mechanics dynamics in civil engineering when civil engineers work on static analysis?

Hi all, I would like to know what is the equation upon which I can use to determine the practical resonance frequencies in a system of second order, linear differential equations. First some definitions: What I mean by practical resonance frequencies, is the frequencies that a second order...

I'm looking at changing my university degree to go back and study science with a major in physics. I've always had a deep interest in the way the world works and how much of what happens around the world and the universe seems to be governed by simple laws, or some cases not so simple. My main...

should n't it be a maximum number to achieve less than 0.5% uncertainty for the last question as you add more disks would there not be more uncertanity therefore as the number of disks for 0.5% is 9.5, 10 would give an unceranity of greater than 0.5% so it should be 9? the answer is 10.

The study of these theories is interesting in itself,if only to understand Godel's work. My question concerns their practical applicability to the solution of problems in different disciplines like mathematics, engineering, physics and the like. Are there reasons for studying them beyond the...

Dear All, I read this article Lightning Strikes Produce Antimatter Particles in Earth’s Atmosphere which I find very intriguing and it raises many questions for me, so I will try to contain myself. Here is the accompanying illustration: The first major question is, how did the researchers...

Homework Statement Why working formula for transverse and longitudinal arrangement in melde experiment different in Melde's experiment ? Homework Equations None. The corresponding equations are all derived from the same fact. The Attempt at a Solution So, I have understood that the tuning...

Hello, I'm looking for a book on relational databases, that uses SQL, that is practical with lots of examples, and the least possible amount of jargon. Specifically, I have issues understanding how to translate the E/R model into the relational model (relations to tables), and the book that I...

Homework Statement I am writing a prac report regarding Hooke's Law, and am uncertain how many significant figures I should write my results in in my results table. I have heard that in my prac report, I must keep my significant figures consistent, that is, all data measured by the same device...

I'm trying to think through a situation, and develop some confidence I've got it right. The situation is a apartment building, about 60'/20m high, with a courtyard in the middle about 60'/20m square. In the middle of the courtyard, is an low exhaust stack, about 8' high and around 8' square...

Need a practical example of E=MC2 with real numbers Ok, so I understand that Energy = Mass of an Object * Speed of light square, if we must convert this to numbers, how can this be presented for let’s say 1,000 hydrogen atoms? Energy = 1.008 (Hydrogen mass) * 1,000 (hydrogen atoms) * speed of...

Good afternoon, I am carrying out a practical magnetism project which involves 2 small (2mm x 2mm - 0.6kg) neodymium magnets attached together, and an electromagnet to create a push-pull force from below in order to part them. For those that also build model railway/railroads, this will be a...

1. What is the advantage of using class 2 laser light? I would really appreciate if reference source is also given!Homework Equations Not needed.[/B]The Attempt at a Solution Well, I thought that using monochromatic light would made it easier to measure the distance between fringes. And also...

Good Evening Mates, I've been following up with the Forum for a couple of months now, and I've noticed how some of the members are able to give some deep answers for seemingly simple questions. I'm in my second year of undergrad's school, and have studied the basis of Mechanics, Thermodynamics...

I'm not a physicist nor an academic, however, the world around me fascinates me. I was watching YouTube and came across an explanation of Bose Einstein condensate, and thought with less space between atoms that would potentially be a better target for creating new elements. So my question is...

Hi everybody! So I got a Masters in physics (precisely - biophysics) 5 years ago. Then attempted to get a PhD, realized that research and academia don't feel right to me and quit. Now I'm 28. Despite the lack of the doctoral degree, working in the lab gave me many skills. Biomedical engineering...

I just have a simple question to ask. I'm simulating an instrumentation amplifier and then testing it practically. When I simulate it, my gain is 6, but when I test it, I get a gain of 5.54. I'm just wondering what is causing the slight drop in gain in the practical results?

I was wondering how I could measure the rate constant k for chemiluminescence reaction of luminol (when oxidised by H2O2. I was told that I can use a lux meter that measures the intensity of light emitted, but I'm not so sure how this can be done since the equation calculating the rate constant...

Homework Statement Please could someone help me with how raw data should be dealt with when using a human operated stop watch. I have attached the information we were given and it makes little sense to me. Homework Equations See attachement The Attempt at a Solution We are constantly reminded...

The "wireless power" thread made me think of this, but I have pondered it before when it comes to microphone arrays etc You can easily find documentation on the interference patterns N in-line sources of waves generate. E.g. The annoying thing here is that you have infinitely extending lobes...

Which course do you guys think would be more interesting/helpful for a physics major? They are both 100 level, Intro consists of two lectures and a seminar a week, and Practical Logic consists of a three hour lecture once a week.

Simple premise: take ohms law with a purely resistive ac circuit. 1 volt through in series with a 2 ohm resistor, I have 0.5 amps of current. I want to maintain constant power. In practice, "how low can I go" with the voltage to increase the current? There's probably many variables I'm missing...

What are some of the practical applications of quantum mechanics that are being utilized to optimize our existence as a species?

It's technically very difficult to create BEC's of atoms, using lasers to cool the atoms to near absolute zero, in a vacuum chamber, and it was only first accomplished in 1995, despite being predicted many decades before that. The atom, or molecule, BEC's so far created are, from what I've...

Homework Statement "We will concentrate on the time taken for the capacitor to discharge to exactly one-half of its p.d, and how this varies with the value of the resistor. So repeat the experiment with different recorded values of R, and find the corresponding T, the time taken for V to fall...

I'm having a hard time finding a starting point for this question. I'm looking for all the variables that can effect the amount generated by induction, and then hopefully ordering them from the most important to least important. Any references to a good starting point for someone who hasn't...

I suppose you recognize, by title, the situation I am referring to. I don't know if physics people get it as often as math people. The situation of course is that I tell somebody that I am studying math, and if I mention some specifics, like mention Topology or Algebra, (which I have to sort...

Hello, i am a high school student who is interested in physics. Me and my friends want to build something cool. Can be anything related to science. Nothing too complicated but nothing too easy. Something interesting and safe. No dangerous suggestions please. I do not have any qualifications as i...

Hello everyone, I have two little clarifications to make about Huygen's principle: - Why doesn't the wave go backward? I mean, if every point on the plane acts as the source of a secondary wavelet, then, along with the envelop which makes the wave travel apparently forward, another should...