Building Definition and 919 Threads

Hey I was wondering if you all could help me. I need to build something that will move a rod of wood back and forth in a fashion similar to a musical metronome. I am hopeing to make it for under 50 dollars and need it to go about 200 rpms at min. ____...

Homework Statement Spiderman steps from the top of a tall building. He falls freely from rest to the ground a distance of h. He falls a distance of h/4 in the last interval of time of 1.2 s of his fall. What is the height h of the building? The acceleration is constant -g. Homework...

OK, so I decided to put together a computer, but I'm having some trouble. Hopefully it's of the "you forgot something obvious" variety, rather than "it's broken". The thread is titled as it is because I imagine that if I fix this problem, others will come up I'll also need help with. So I...

I found an old circuit diagram online but have never been able to find it again. Here is what I am trying to do: The three-phase DC motor I am working with is a 4-pole motor. Therefore there is a direct relationship between the frequency between the motors phase-leads, and the current RPM of...

Hi folks, I am new to PF. First I have to apologize for the following english -- it is not my native language. I have problems in understanding the formation of the conduction and valence bands of solids: For example in III-V compound semiconductors both constituents are sp3 hybridized...

so i just survived my first semester at a real college, (transferred from community college), and got my A@# handed to me. I did however pass everything and learned a ton. I learned what real studying is and that I am probably not cut out for grad school, but we shall see. i am curious if its...

I am building a Pinewood Derby car (Just for fun) and I want to make my car REALY areodynamic, but I don't really know the basics of areodynamics. Please help!

Anyone know how to do it? I do not know where to find dee electromagnets, nor do I even have the complete design of his system.

1. Suffer extreme symptoms from Microwave RF emissions cell phones, Wi FI, Cordless computers and RF Routers. 2. The next door neighbour has installed a Uniden DECT that transmits continually 24 hours a day. Our bedroom and the next door neighbours loungeroom is separated by a normal...

I would like to build a particle accelerator as a science project. I know it may be unrealistic, but depending upon the size and complexity that I choose, it should be possible. If anyone could help with the construction process of a small particle accelerator(preferably circular), I would...

Hey PF, I want to resurrect an old robot radio I have sitting around. What exactly is involved with building an AM/FM receiver?

Hi, I've got two related questions. You can decompose a (semisimple) lie algebra into root spaces, each of which are 1-dimensional. If X has root a and Y has root b then [X,Y] has root a+b. If the root space of a+b is not zero (i.e. there is a root a+b) then is it possible for [X,Y] to still...

Hey there PF! I'm currently working on building an Infrared Remote to control a series of triacs. The objective is to create a "remote control power bar". The original plan was to use push button switches to toggle the Q lead of a 4013, each of which houses two switching circuits. Q and NOT-Q...

I'm sorry about posting this here.. it's not homework don't worry :-p But I just feel that there must be a more specific subthread for it than general physics, but nevertheless I suppose a moderator can move it if they are aware of such a subthread? Anyway onto the actual thread: Basically...

***Building a pump from scratch, engineering competition*** Hello everyone. I have been entered into a competition. The spec is to build a pump that can pump 30 litres of water a minuet for 30 minuet to a height of 4 meters. The pump has to be built over 3 days (18hours) but i have...

Hi everyone, I want to ask everybody if someone knows a book, or some lecture notes available on the net, to lear how to decompose the Lie Groups in irreps in physical notation, like 8_v \otimes 8_v=1+28+35 that can be found everywhere on books like BB&S or Polchinski. It is really hard...

I found this link and thought it may be of some use to build a power supply. I know that these power supplies can pack around 500W on the right power supplies. Is there anything I should know and be careful of when making this and when playing with smaller electronics...

Homework Statement I need to build a faraday flashlight and I have two problems. Homework Equations (1) When I use a 12V DC motor connected in parallel to a capacitor (16V 2200uf) and then to an LED assembly, I can't get the capacitor to charge. (2) If I wanted to use a magnet and coils...

Could a new universe be built with purley information, i do not know how to explain this question any better without corupting it in some way, may be a lesser question is, is matter, energy purley information.

Homework Statement Suppose a stone is thrown from a 45.0 m tall building at an angle 26.0° below the horizontal. If it strikes the ground 30.3 m away, find the following values. (a) time of flight __________s (b) initial speed _________ m/s (c) speed and angle of the velocity vector...

I'm building a tank circuit and I need to know if a ground connection is needed.

I'm taking an intro electronics class and I'm really enjoying it. I want to be able to work with electronics in my garage, I have a proto-board and but I would like to build a power supply that can go from 1vdc to 15vdc, this is what my class has. I've looked on the net for instructions, but...

1. This was just a quick question that I was thinking about. If you jump of a really tall building, let's say 100-story building and you fall most likely you won't live to tell the tale. But let's say you jumped with a cardboard (or any object) and a couple feet before you hit the ground...

Allow me to be so bold as to ask,how do you build an Electronic Inclinometer to measure a boat tilting until it reaches a 5 degree angle. When the boat tilts to a 5 degree angle, the inclinometer has to be able to read the 5 degree. The Inclinometer has to be waterproof because it will be...

Im trying to do just that, that is build a timer that countsdown accurately to the minute. Ideally this device should have a range of about 5 second countdowns to 36 hour countdown. I'd like to add a 7-segment LED display wired to count as well but I am not sure I think i can do that with a 555...

I am supposed to make a car similar to that of a mousetrap car, except without using a mousetrap. I have basic materials and I am completley dumfounded when it comes to making the car "go." please help me! i am so desperate! i originally thought that using a car to make the car go would be...

Assume a rigid building(assume the building to be like a pyramid and its empty inside) to be vacuum. If we open a hole(about r=.5m), then, how long will it take for the air to take up of the whole space apprximately? Will, it's just curiosity because I found a little pump in a class room...

I need to build a timer(using a 555) with a frequency of about 1KHz and a duty cycle of about 25% to provide my clock signal. So the 555 is obliviously in astable mode. From my engineering data sheet: D=\frac{R_B}{R_A+2R_B} f=\frac{1.44}{\left(R_A+2R_B\right)C} where C is my capacitance value...

Homework Statement Use the given information about the asymptotes of a function to write an equation for a rational function. You may leave your function in "factored" form. Homework Equations 1. Vertical Asymptote at x=3 and x=-2 2. Vertical Asymptote at x=5, Horizontal Asymptote...

Homework Statement Take up as positive. A rock is projected from the edge of the top of a building with an initial velocity of 16.5 m/s at an angle of 40 degrees above the horizontal. The rock strikes the ground a horizontal distance of 82m from the base of the building. The acceleration of...

This semester, we have to build a database management system (DBMS) as a mini-project. We do have the database theory course covering database management concepts, sql and pl/sql. The project is to be done using Oracle and possibly Visual Basic for the front end and maybe a programming...

Hello, I'm tasked with building a queue from as many stacks as I'd like, trying to get the fastest implementation possible. The best I can think of is using two stacks and as you enqueue items you push them on the first stack stack, but every time you want to dequeue if there are n items...

Hi there, For a personal project of mine, I have been designing a low-noise linear power supply to provide power to guitar effects pedals. A couple guitarists I know use a hodge-podge of AC adapters and switched PSU's to run their various pedals (sometimes 8 at a time). This mixture of...

im working on a ship that can fly; simple yes . well having a little trubble tring to found out how mutch HP is needed to lift one pound in the air. I am making the engine my self i can't really give to mutch information at this point in time becouse I am still working on the frame work for...

greetings :) so I'm pretty stumped on this one question from masteringphysics: A ball thrown horizontally at 23.7 m/s from the roof of a building lands 35.0 m from the base of the building. How high is the building? i first listed all of my given values ---------------------------...

Homework Statement "In a chase scene, a movie stuntman is supposed to run right off the flat roof of one city building and land on another roof 1.6 m lower." "If the gap between the buildings is 4.5 m wide, how fast must he run? " Homework Equations Vf^2 = V0^2 + 2a (Xf-X0) This...

I have a few questions and verifying statements regarding the concept as well as practical building of Faraday Cages. 1. A Faraday cage's mesh must have a grid with a spacing less than that of the wavelength that is intended to be stopped. 2. Why is it that foil and mylar also work as...

Design a method to calculate the height of a building?this is an engineering design question... URGENT! ...i need inputs !

Hi! I`m new here and I need some info where I can find project about building Geiger counter and where I can order the electronical components with shiping to Europe (Macedonia) :confused: Please help me!

hey every1.. at the moment for a school project a group of mates and i are building a rat trap operated car. This is made by obviously a rat trap with about 5mm diamater front wheels and cds as the rear wheels... this is just a quick explanation. what i need to do is find out how far the car...

Alright, I need this information not for science homework, but for writing a short story. You see, I am very particular about the tiny details, and in the story there is going to be a superhuman jumping off a building. I want to know the speed of such a jump to dramatise the description, but...

My name is Dain, and I'm wondering if someone would be able to help me, or point me in the right direction on designing a aerodynamic 3 wheeled billy cart. Once a year at my old home town of Beechwood in NSW, Australia, is a 5.6 km 2 person billy cart race down Pappinbarra Mountain...

Could i have some help with the following: Design, floor joists in a domestic building to span between walls 3.0m apart. the construction of the floor is 18mm timber boards joists 15mm overall plasterboard + skim coat The joists are 50mm wide and at 450mm centres The permissible...

rock is thrown from the edge of the top of a 100-ft tall building at some unknown angle above the horizontal. The rock strikes the ground a horizontal distance of 160 ft from the base of the building 5.0 s after being thrown. Assume that the ground is level and that the side of the building is...

I'm a beginning QFT student, trying to slog my way through Slansky's http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVP-46SPHMC-94&_user=4422&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000059600&_version=1&_urlVersion=0&_userid=4422&md5=c09eed961c9201786651592d71de94f3"... I...

Hello, I'm looking to build my first telescope from http://www.apogeeinc.com/product.asp?itemid=766 (PDF file). My question is this, is this a suitable guide in doing so? If not what steps should i take to successfully complete this task?

Homework Statement A rectangular building is being designed to minimize heat loss. The east and west walls lose heat at a rate of 10 units/m^2 per day, the north and south walls at a rate of 8 units/m^2 per day, the floor at a rate of 1 unit/m^2 per day, and the roof at a rate of 5 units/m^2...

Could anybody please assist me. I need to regulate 12 volts dc from a car battery down to 1.24 volts dc yet I still need to be able to draw 12 - 15 amps. Ideally I would like to be able to adjust the voltage. Does anybody have any ideas how I will be able to achieve this & if so, what...

Electric car, it has to have a 50 mile range before recharge, carry two people with room for cargo (shopping), be a home garage project, i have been looking round and think the WarP motor and Zilla controller are a good drive system run on 72 volts. Would a fiber glass monocoque with molded in...

I'm trying to build a motor like the one in this http://youtube.com/watch?v=h6Ev64h49wg&feature=related". I can't seem to figure out how the split ring works. From what I can tell, only one solenoid would be powered at a time, but wouldn't that be inefficient? Also if only one is powered...