Hi Definition and 291 Threads

hi colleages. is Bernoulli-Euler theory valid in the dynamic analysis as following: M/EI=1/R where, M= moment EI=stiffness R= curvature is this equation valid when M becomes a function of x and t, as follows: M(x,t)/EI=1/R

Hello Back again for another round of making the "resonant electrostatic water capacitor" aka water fuel cell aka hydrogen generator.kl The "[URL out"]instructions[/URL] say to use a high impedance circuit, which pulses high voltage to the electrodes at a very finely adjustable rate. Two...

Hi! There is no structural/civil section! Is structural/civil not highly regarded in America? For you civils/structurals: What would you recommend as a good speciality in civil/structural engineering, and why? I'm not looking for the usual listings of specialities, but if anyone has any...

hi everyone... i am dong my project designing a 3d solid state hi everyone... i am dong my project designing a 3d solid state accelerometer.The accelerometer should detect and measure steps. Can anyone of you help regarding the design of it...

Hi all. I apologize in advance for the long post, but I can't really relate to many people and am hoping you all can offer some invaluable advice. I've recently been enjoying being alone, doing absolutely nothing a lot more than being with others. I had a group of friends throughout middle...

This is a great forum! It was recommended to me by a friend on baut. Much more interesting tho from first impressions. (Sorry if there's a thread to enter on, I couldn't find it). Hi all!

I do not know if works the same everywhere, but as a freshman in university I am really new to this. My professor gives us assignments, even-numbered assignments, on our homework. Now being the youngest person in my class and not knowing anyone is a disadvantage. Because those assignments my...

Hi, my name is Luis and I am a High school student currently enrolled in Foothill High School. I need to interview someone in the profession of Engineering, someone who is willing to speak face to face and discuss the advantages/disadvantages of being an engineer.

Hi, what is the use of PFC?

Just popping into say hi again, it's been some time since I have posted here. I see a lot of familiar names and it is good to "see" everyone! Since I have last visited, I re-enrolled in college and am studying accounting (a far stretch from philosophy!). Hopefully will be around more as I am...

Homework Statement A 3.80 kg block is in equilibrium on an incline of 38.4◦. The acceleration of gravity is 9.81 m/s2 . What is Fn of the incline on the block? Answer in units of N. Homework Equations The Attempt at a Solution FgsinΘ=mgsinΘ=3.8*9.81*sin38.4°=24.04...

Homework Statement It is a windless day at standard temperature and pressure. A golf ball of mass 45.5 grams and 4.25 cm diameter rests on a golf tee. It is hit by a golf club in an elastic collision with inclination pi/6 and force 16k Newtons. During flight, the air friction is 0.25 Newton...

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

Hello I'm in ninth grade and this is the first time I take physics I wasn't doing well at first but now I really like it and I want to major in physics in university. I have an 18/20 in physics and 19/20 in maths is that good for my class or should I be doing better to study physics in...

Homework Statement The question involves a HI could in the ISM with an observed 21-cm emission line. I'm asked whether formation of molecular Hydrogen is likely. Homework Equations Not entirely sure The Attempt at a Solution First of all, I should say that this is a...

Hi I would really appreciate some guidance. I am currently enrolled in an engineering program and am about to finish my first year. The program i am is has a common first year then branches off in second year, i plan on perusing Engineering Physics. I have a very deep interest in...

Homework Statement How much dcm3NH3would we get if 2 mole of N2 react with the same amount of H2 Homework Equations I tried this n=V/Vm then get V=n x Vm then get 2 mole x 22.41 dm3 x mole -1then get 44.82 dcm3 but i don't now if it is right so any help would be great The Attempt...

Homework Statement the parametric equations of the motion are x=(t)^2m and y=(6t-1.5t^2)m i need to find the velocity at the time moment of t=2s Homework Equations The Attempt at a Solution so this are the four solutions v=o,v=2m/s,v=4m/s,6m/s .

Hi, I keep confusing myself between decoherence and the transition from pure to mixed, both of which, as far as I know, come about due to the interaction of a system with the environment. I like to think about things in terms of the density matrix to get it solid in my head. Can someone...

hi, i have a question about "Gravitons" do gravitons exist? I'm wondering what is gravity made up of. as they say light is made up of photons, then what is gravity made up of? or is it only that fabric of space-time that takes place here?

Hi. Say we want to parametrize the plane R^2. This can be done for example using (x,y) cartesian, i.e. a pair of intersecting lines, OR (r,theta) polar coordinates, i.e. a half line intersecting a circle. But it cannot be done using (x,r) coordinates, i.e. a line intersecting a circle, because...

Hi everyone, is 'X' be capitalized in 'x-ray'? i noticed in physics journals, for e.g., in phys. rev. lett., it is not capitalized! which is correct ?? or just it is a matter of personal taste? actually a silly doubt thanks for replying

Hi ,new here and have a question! :) Hi all.. ok I am trying to teach my self the best way i can about flight physics. I am an avid avation fan and have been for a long time, i fly planes my self as well as RC planes / helicopters so I am not entirely new to them, but true physics of flight is...

Hi, I really need help with my homework! I had a home work, it is like: I have a data table, that has Initial Position: 1.652m from the sensor Final Position: 0.977m from the sensor Initial Velocity: 0.003m/s Final Position: 1.366m/s Angle: 27 degrees g = -9.8m/s^2 U represent...

Hi - -- I want check my answer Hi - -- I want check my answer if this answer is ok which graph1 or 2 I do in exam

hi there question 1 why does the pitch of a siron on an emergency car change as it comes and then goes. 2 I've tryied to understand e=mc2 with some difficulty but what i did understand is that the faster an object travels the more energy it needs the more energy it has the more mass it has...

http://www.webassign.net/sercp/p4-62alt.gif (Figure P4.62) Three objects are connected by light strings as shown in Figure P4.62. The string connecting the m1 = 5.00 kg mass and the m2 = 4.00 kg mass passes over a light frictionless pulley. a) find the acceleration of each object and b) the...

I found I had a new niece the other day! She is getting her PhD in Planetary Geophysics and she's joined PF! Her name is Anastasia and she is from Latvia, she is my brother's wife's niece, making me her Aunt, apparently. She just signed up, so hasn't posted yet, but you can leave her a...

first timer here and non english spoken so I might get few mistakes but but... Question is about static equilibrium and about with clock and against clock principe. When figuring out momentum til a point first we define if its positive or negative. I understand that its our choice to define...

Despite our allergies, etc, my wife and I have been wanting a dog to share our small place with. Here is a really bad flash-shot of Duke. He's a 2 year old boxer/chocolate Lab mix. We just took him to visit Max the Wonder Dog (pit bull/German shepherd cross) who lives down the road, and there...

I want to know efficiency of a tractor mounted equipment. my input is only this-- tractor is a diesel engine powerd one with max. 200nm torque ,6o hp.@1500 rpm. the equipment runs on 100 rpm after a series of gearing. i just want a rough idea about efficiency. how mutch H.p...

I'm as happy as a kid in a candy store. I've stumbled across an active forum on Physics <3. yippy! I love maths so much! Physics, on the other hand, bugs me. Physics is like an unremitting nag, poking and tugging at me. I can't set it down. =) I'm so excited about PF. Hopefully you...

Homework Statement http://people.hofstra.edu/stefan_waner/Realworld/calctopic1/derivgraph.html this is the problem solution, after I saw it, I still don't understand how did they make the chart, which have f'(x) values. What equation should I use in this case? Homework Equations a=dv/dtThe...

Well, I couldn't find an "Introduce Yourself" thread anywhere and I've made two posts on here out of the blue now so I figure some sort of introduction is in order. Hello, nice forum you have going on here. So which OS (Operating system) do you use? I'm currently using Windows XP and plan on...

Homework Statement Thank you very much in advance if you help me to resolve this problem. I am 3D designer and I must to defend that the object is visible from the beach but so small. sorry my english! Please if you can contribute with formulas and solve the problem will be valued, because...

Hi there i need to know when capacitor is used in A.C CIRCUIT ( not for the D.C CIRCUIT) ,if we have incoming current frequency is 60 Hz ,so does it means that for one second a capacitor charge 60 times and discharge 60 times in a second or it charges only once and discharge when it is...

Homework Statement Consider an HI cloud of temperature T ≥ 3 K. a) Calculate the energy level difference between the hydrogen atom states leading to 21cm line emission. Show that the ratio of hydrogen atoms in the upper to the lower state of the 21 cm line is approximately 3:1. b)...

Anyone know how to tell which USB ports are "Hi speed?" I read something about some of the USB ports on a computer being hi speed allowing for faster file transfers. I am backing up my system now to do a factory restore and I want to make sure I am using the fastest ports since these 8 GB...

Well hi. I am in 7th grade and I am learning physics. Me and my friend saw a vid on 1 of Newton's theroys. It was "time goes slower while moving faster", if i recalled right. and me and my friend wanted to go past the speed of light to break the time barrier and make time stop from Newton's work...

A teenager pushes tangentially on a small hand-driven merry-go-round and is able to accelerate it from rest to a frequency of 15 rpm in 10.0 s. Assume the merry-go-round is a uniform disk of radius 2.5 m and has a mass of 760 kg, and two children (each with a mass of 25 kg) sit opposite each...

Hello Everybody! Have any suggestions how to solve this differential equation, I haven't.. :( y(y-2x(y'))^3=(y')^2

Would it be feasible theoretically to use a continuous endothermic fusion reaction as a high-energy heat sink? Would such a process be capable of producing unstable isotopes for use in nuclear fission? I ask this as a science fiction writer and I would dearly love input and even direction or...

1. Is there any formula for calculating the leakage current carried by a dielectric in a capacitor? 2. A battery-powered light bulb has a tungsten filament. When the switch connecting the bulb to the battery is first turned on and the temperature of the bulb is 20 ^\circ {\rm C}, the current...

Hi to all. I'm Emiliano, I'm from Italy. I'm studing Astrophysics at the University of Trieste. Hope to find here many friends with whom have many nice discussion!

Homework Statement A jet engine gets it thrust by taking in air, heating and compressing it, and then ejecting it at a high speed. IF a particular engine takes in 20 k/g of air per second at 100 m/s and ejects it at 500 m/s calculate the thrust of the engine. chriss #getmoney: thrust of the...

Hi hi any friends from physorg here?

Homework Statement In a mall, a shopper rides up an escalator between floors. At the top of the escalator, the shopper turns right and walks 9 meters to a store. The magnitude of the shopper's displacement from the bottom of the escalator is 16m. The vertical distance between the floors is 6m...

Hi I'm new to physic. "What does 'traverse' mean?" So like I am a junior in high school taking Physic. In my book, it uses words that I don't understand. For example, the word 'traverse.' what does it mean?

I was wondering if questions about Integrals are best suited to be posted in the Differential equations forum? I didn't see a dedicated forum for it. Thanks, Steve

hi all... I'm new...:smile: hi all... I'm new...:smile: