Revision Definition and 52 Threads

Hello, I know I read this somewhere in ASME standards, but I can NOT, for the life of me, find it again. I believe it says you're supposed to delete old revision clouds on a drawing when putting a new revision on the drawing. I read Y14.35 "Revision of Engineering Drawings" 2 or 3 times and I...

Hi, I'm a 3rd year (Scottish so a 4 year undergrad degree) student doing Physics. Obviously many of you will have been through a Physics/Maths degree and this question is for you. I'm finding that the volume of content this year is so much that I spend all my time keeping up on course notes...

have a Summer Exam , at the begging of next week on all topics that we have done , so I decided to do Algebra , but I forgot have to do it , because it was a while ago, can anyone show me the method again please to memorize. Thanks in advance . Workings : add 4x+5=9 3x+6=9 9/3 =3/3 3x=3

Homework Statement For x,y,z ## \in \mathbb {R^+} ##, prove that ## \sqrt {x (3 x +y) } + \sqrt {y (3y +z) } + \sqrt {z(3z +x)} \leq ~ 2(x +y+ z) ##Homework Equations The Attempt at a Solution I don't know which inequality among the above two has to be applied. I am trying to solve it by...

As the title states. There's been a flurry of research being done in Japan on a banned topic related to "LENR". I was wondering what is the burden of proof required to change minds on this topic? How or where may it be presented? Is the guiding principle that if it cannot be described by...

Homework Statement A cylinder of mass M and radius R rolls without slipping on a plank that is accelerated at rate A. Find the acceleration of the cylinder. Homework EquationsThe Attempt at a Solution Physical force acting on the system : Fphy = N + mg + fr w.r.t. plank frame i.e non -...

This is an idea I've been thinking of for a while. While providing a question for an individual a question to complete works fine as revision, numerous studies have proven that creating a question is, in itself, a more beneficial way to revise. Instead of simply recalling a process or equation...

Homework Statement See image attached, have completed the parts a and b using steam tables and interpolation and got the answers a) Wet steam h at 10.5 bar: h = 2378 kj/kg b) Superheated steam at 10.5 bar @ 285 Degrees Celsius: h = 3018.12 kj/kg Which I believe to be correct now, parts c,d...

I know this is mainly a site for scientific discourse. But anyone good at writing English herer? I have this paper coming up and my teacher is extremely specific about word choice, tense(s), "to be" verbs and more of those types of things. So my topic of the paper "Geothermal energy" I must...

I'm studying for my prelim and am trying to understand inductance better based on some questions I have done I've come up with these statements can anyone confirm they are true the back emf in an inductive circuit at any given time equal to the voltage across the inductor I initially thought...

< Mentor Note -- Thread moved from the Calculus forum to HH/Calculus >[/color] Hey everyone, I've started my new course and have been given revision and tutorial questions to do at home, this question has been bugging me for days now! I need to make "t" the subject to allow me to progress into...

Your help would be greatly appreciated 1. If an object is dropped from a cliff, how many seconds will it take to have a speed of 80m/s? would gravity be taken into account? This question seems weird because you usually get given 2 variables to get the third, unless I am missing something...2...

Two waves are identical apart from a phase difference, they create a resultant wave of 25% increase of the original amplitude, what is the phase difference. sin(alpha)+sin(beta)=2sin(1/2)(alpha+beta)cos(1/2)(alpha-beta) Asin(kx+wt)=2sin(1/2)(alpha+beta)cos(1/2)alpha-beta)...

In your experience, how often does it happen that a submitted paper is accepted for publication without being sent back to the author for revision? I was speaking with the former editor of a notable journal in my field and he said that during his multi-year tenure he only saw one paper be...

Hi everyone, I got some past papers to revise for my second year final exams in may the course I am in is called electrical and electronic engineering (I am studying in the uk). I was just hoping if any of you guys know any good youtube channels like khanacademy but for engineering topics...

Okay so I'm using ncbi and when using the nucleotide database, when I access the revision history of a result of any query, I get a lot of sequences. Surprisingly they all are of the same version. Why? If each is different shouldn't they have different version numbers? They all have different...

Hi guys, Revision for an exam tomorrow, I hope someone can help? I've been given the answers but I can't work out how to find the damping ratio without being given a velocity or distance for the mass to travel?A mass of 6kg is suspended on a spring and set oscillating. it is observed that...

I came across this question on a past paper and would appreciate some help. It is too hard for me at the minute. The problem - The volume of a body whose surface is formed on the underside by the paraboloid z = x2 + y2 and bounded on top by the cone z = 3-2(x2 +y2) (a) Explain which...

Homework Statement I've spent the last hour trying to get this, and it's starting to drive me crazy! I'm not sure how to approach the waveform, as there are two forms? I'm guessing that the period in this case is 4 seconds, and they've included a second wave to reiterate that? Homework...

Hi there, I am a Physics teacher hoping to set up an amazing Physics revision website, and wanted to canvase opinion on the domain name. Unfortunately physics.com does already exist - its not being used for anything and I can't contact the owner to ask about transfering it :frown: Would've...

Hi, I'm sorry if this question has been answered before, but I was wondering whether anyone had seen the '30 Problems with the Big Bang article? I'm not a physics student, but I've a keen interest in it, and the Big Bang has always been a particular point of fascination for me and this paper...

Homework Statement The problem is attached as an image. Note this is from a past exam. Homework Equations Conservation of angular momentum. Rotational kinetic energy. The Attempt at a Solution a) The moment of inertia of the man and stool is given as 3 kg m^2, and the dumbells...

I'm a Year 12 (UK) Physics student, currently in the first year of my IB course. I have been assigned some Easter revision work, and just wondered if anyone who has experience of IB Physics has any recommendations as to which books they have used in the past. I have been given two hefty...

Hi, I know next to nothing about abstract algebra (had one intro-class years ago), so sorry if this is a dumb question. I was browsing through "A book on abstract algebra" by Pinter and had a thought. In the chapter called "ruler and compass" (chapter 30) he talks about how abstract algebra...

I am trying to revise for PhD, going over MSc work. Could anyone help me with this question? Homework Statement A pion traveling at speed β(=v/c) decays into a muon and a neutrino, π→μ + \nu. If the neutrino emerges at 90° to the original pion direction at what angle does the muon come off...

I’ve been saying it for a while now, but a new report by the U.S. Department of Education confirms that Minnesota’s anti-bullying statute is the weakest of the forty-six states it analyzed (four states, however, lacked state-wide polices altogether). *At … Continue reading...

Homework Statement Solve -x1 + 6x2 -2x3 = 0 5x1 + x2 + 2x3 = 0 over Z7 Additional Question: How can we immediately tell there is more than one solution?Homework EquationsDon't know. The Attempt at a Solution [-1 6 -2 0]_________[ (-1mod7) 6 (-2mod7) 0] [5 1 2 0] _____=>...

Homework Statement Thanks to everyone who has helped me so far - I'm very grateful. (1) Prove that the multiplicative inverse in any field is unique (2) Prove the cancellation law | ab = ac => b=c (3) Prove (-1)a = -a Homework Equations The field axioms...

Homework Statement I have a test on Energy in a few days, I'm in the top science class at my school (grade 9). Homework Equations The test is on stuff like, Kinectic Energy, Potentional Energy, Renewable Energys etc. If anyone on here can help me, It would be greatly appreciated...

Hey guys, I'm trying to revise for a DSP exam I have this week and I'm looking at past papers I have. I've got the question, and the out and out answer but it doesn't show the workings so I'm struggling to find out how to get there;For the following periodic digital signal...

I need to find the Fourier transform to this function and I'm really stuck, because i tried substituting it into the Fourier transform equations but i started to get a really long integral that got out of hand! i also know that but i don't know how to incorporate it into finding the Fourier...

Do you follow a somewhat strict timetable? Or do you, like yours truly, just start working spontaneously on a few chapters and be done with it? At times, something ticks and everything about Mathematics/Physics seems fascinating and it keeps me going on and on. The problem which comes with this...

Homework Statement In 6th edition of Engineering Mathematics, Programme F2 Intro to Algebra, so far I get it all there, but I'm stumped on one question in the revision excercise, it goes like this: ((2a-3)/4b)+((3a+2)/6b) Homework Equations He then goes on to break down the answers...

Homework Statement A baseball player friend of yours wants to determine his pitching speed. You have him stand on a ledge and throw the ball horizontally from an elevation 3.00 m above the ground. The ball lands 30.0 m away. A) What is his pitching speed? B) As you think about it, you’re...

Attached is a question from my book, I know that the answer is 112KN but can't work out the method for getting there. Hope you can help, James

I'm doing some past exam papers to revise for my test on thursday. And I can't work out the last question in this problem. I worked out the time for one complete cylce is 50 microseconds, and the frequency is 20,000Hz, 1/Time period. I can't work out the last bit though.

Hello, I am having issues with some nuclear physics revision questions Homework Statement The following atomic masses have been determined (in Atomic mass units, u) (A = atomic mass number, Z = proton number) Li(A=7,Z=3) - 7.0182 u Be(A=7,Z=4) - 7.0192 u Indicate the stable nucleus and...

Hello PF readers, I am currently doing Further Mathematics, and I was looking for a suitable revision guide for Further Pure 1 for ME, but I was unable to find one. Are there any attention worth revision guides that offer good explanation about the topic with given examples and questions to...

Hi this is my first one so i need help. I have GCSE physics exams soon and i need some help with revision. Just tell me anything that you can that you will think will help me. Thanks

Can you help me with some of these questions? I can't do the second part of Q1!

The Monty Hall Problem states that during a gameshow, a contestant can choose one of three doors. One of these three doors contains a car, whereas the other two doors contain a gag prize. After selecting your door of choice, the host will open one of the two gag prize doors. At this point, is it...

Hey I have a Physics exam in a week’s time which covers Optics, Nuclear & Particle Physics. They are all third year courses and the exam itself is one that I really need to pass – and get a good grade in. I have been revising for about two months but I still can’t say that I’m comfortable...

Revision on Past Exam Paper ! Hey there, i am stuck on this question in my past exam paper, and i have tried many ways of doing it but just simply not getting any where ! So please would u mind helping me out a little here !?? A rectangular cross section hollow steel tube (outer diameter 50...

I am currently in year 12 in england taking maths, further maths, chem, physics and geography. I get fairly good grades and aced my gcses last year, but i have realized that i have NO method for revising, and it is starting to show up in tests. I wondered if anyone could tell me if they have...

If a tensor equation is true in all reference frames and vectors are tensors of rank 1, then why aren't equations involcing velocity or momentum true in all reference frames? why do they have to be revised, as, say, in special relativity ( the lorentz transformations)? thanks

At the mo I am in the first year of a levels and i was taking chemistry, biology, maths and physics. but physics really sucked as the teachers were always 15- 20 mins late, and the course is rubbish as its based in really life, so all the questions were like " in the mid 1880s american...

hi okay i have a question, it is an old test question so it would be nice is someone ans b4 8am cos that is when the test it but if not that is fine just incase someone is surfing this website at this time.. ha.n e ways the question is a 25mH inductor is connected in series with a 20ohm resisto...

Guys I need a fast algorithm to perform division with a remainder. It has to be very fast though...

I'm doing some Maths revision for my impending GCSE tests later this year. I have a (few) question(s) that I need explained to me in very simple easy methods. Beware - there will probably be more questions. Thanks peeps. Here's the first question I need help with...

Exam revision question. Help! Hello. I have a thermodynamics exam tomorrow. This is a past exam question and I'm not doing very well with it. If anyone has any ideas please help! A charge enters a spark ignition engine at 330K and 1 bar, and is isentropically compressed through a ratio of...