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Pulley |
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Info: Biography, Pictures, Discography of all CDs & DVDs |
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| For the band, see Pulley (band).For the village, see Pulley, Shropshire.Pulleys on a ship.In this context, pulleys are usually known as blocks.Pulleys are used to change the direction of an applied force, transmit rotational motion, or realize a mechanical advantage in either a linear or rotational system of motion.Rope and pulley systems
1.Rope and pulley systems
Rope and pulley systems (the rope may be a light line or a strong cable) are characterized by the use of a single rope transmitting a linear motive force (in tension) to a load through one or more pulleys for the purpose of pulling the load (often against gravity.They are often included in the list of simple machines.In a system of a single rope and pulleys, the mechanical advantage gained is ideally the number of pulleys in the system (if one pulley is used only to change the direction of the load).Since a slender cable is more easily managed than a fat one (albeit shorter and stronger), pulley systems are often the preferred method of applying mechanical advantage to the pulling force of a winch (as can be found in a lift crane).In practice, the more pulleys there are, the less efficient a system is.This is due to sliding friction in the system where cable meets pulley and in the rotational mechanism of each pulley.It is not recorded when or by whom the pulley was first developed.It is believed however that Archimedes developed the first documented block and tackle pulley system, as recorded by Plutarch.Plutarch reported that Archimedes moved an entire warship, laden with men, using compound pulleys and his own strength.Fixed A fixed or class 1 pulley has a fixed axle.That is, the axle is "fixed" or anchored in place.Movable A movable or class 2 pulley has a free axle.That is, if one end of the rope is anchored, pulling on the other end of the rope will apply a doubled force to the object attached to the pulley.Compound A compound pulley is a combination fixed and movable pulley system.In equilibrium, the force F on the pulley axle is equal and opposite to the sum of the tensions in each line leaving the pulley, and these tensions are equal.Another simple pulley system similar to diagram 2, but in which the lifting force is redirected downward.The simplest theory of operation for a pulley system assumes that the pulleys and lines are weightless, and that there is no energy loss due to friction.It is also assumed that the lines do not stretch.The single fixed pulley is installed on the crane.The two movable pulleys (joined together) are attached to the hook.In equilibrium, the total force on the pulley must be zero.This means that the force on the axle of the pulley is shared equally by the two lines looping through the pulley.The situation is schematically illustrated in diagram 1.For the case where the lines are not parallel, the tensions in each line are still equal, but now the vector sum of all forces is zero.The product of the weight lifted times the distance it is moved is equal to the product of the lifting force (the tension in the lifting line) times the distance the lifting line is moved.The weight lifted divided by the lifting force is defined as the advantage of the pulley system.It is important to notice that a system of pulleys does not change the amount of work done.The pulley simply allows trading force for distance: you pull with less force, but over a longer distance.In diagram 2, a single movable pulley allows weight W to be lifted with only half the force needed to lift the weight without assistance.Force x distance) remains the same.W, with an additional pulley redirecting the lifting force downward.An additional pulley redirecting the lifting force has been added.Note that the axles of the fixed and movable pulleys have been combined.The addition of a fixed pulley to the single pulley system can yield an increase of advantage.In diagram 3, the addition of a fixed pulley yields a lifting advantage of 3.As in the case of diagram 2a, another pulley may be added to reverse the direction of the lifting force, but with no increase in advantage.This process can be continued indefinitely for ideal pulleys with each additional pulley yielding a unit increase in advantage.For real pulleys friction among rope and pulleys will increase as more pulleys are added to the point that no advantage is possible.It puts a limit for the number of pulleys we can use in practice.The above pulley systems are known collectively as block and tackle pulley systems.In diagram 4a, a block and tackle system with advantage 4 is shown.Other pulley systems are possible, and some can deliver an increased advantage with fewer pulleys than the block and tackle system.The advantage of the block and tackle system is that each pulley and line is subjected to equal tensions and forces.Efficient design dictates that each line and pulley be capable of handling its load, and no more.Other pulley designs will require different strengths of line and pulleys depending on their position in the system, but a block and tackle system can use the same line size throughout, and can mount the fixed and movable pulleys on a common axle.This allows for mechanical power, torque, and speed to be transmitted across axes and, if the pulleys are of differing diameters, a mechanical advantage to be realized.Look up Pulley in
Wiktionary, the free dictionary.This page was last modified 04:22, 11 January 2008.All text is available under the terms of the GNU Free Documentation License.Pulley is a Southern California punk outfit that made its debut in 1996.Los Angeles Dodgers, among others).Pulley's initial lineup included drummer Jordan Burns (Strung Out), guitarist Jim Cherry (also formerly of Strung Out and Zero Down), guitarist Mike Harder, and former Face to Face bassist Matt Riddle.All text is available under the terms of the GNU Free Documentation License.See Copyrights for details."Click here for maps of great lots!""The time to buy is now!"Don't let Cape Coral investment property pass you by.It's the best value in Waterfront Property in
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lots will always be in demand, and the availability is decreasing with every new home start."Click HERE to see the BEST Freshwater lots!Pulley: This simple
machine is made up of a wheel and a rope.When you pull on one side of the pulley, the wheel turns
and the load will move.Pulleys let you move loads up, down, or
sideways.Pulleys are good for moving objects to hard to reach
places.This crane uses a pulley to move the heavy wrecking
ball.Without the use of a pulley, the wrecking ball
would be very hard to move.This site is no longer being maintained, but will remain online for the use of educators."Are you sure you want to block this user?"Official Pulley MySpacerun by the band!"Pulley DVD available from www.Click here to buy it from us
Click here to buy it from Interpunk.What would you do if you got kicked out of your own band?This informative DVD tells the story of the first ten years of Pulley, from the band's humble beginnings as castoffs from other established bands to successfully carving a niche in the punk rock world with multiple records and tours.Epitaph and contributed many songs to countless compilations.As they prepare to begin work on the sixth record, Scott Radinsky (vocals) and Mike Harder (guitar), Jim Blowers (guitar), Tyler Rebbe (bass) and Tony Palermo (drums) want to share their story.The Swellers (ON TOUR NOW!NEW MYSPACE CONTEST UP!!Thanks for adding Ilium!Big fan of Scott since Rev and his reliever days with my beloved Dodgers.Will i ever get a chance to see you?Hey guys, been listening to you for years but have yet to have the pleasure of seeing you live, or meeting.You guys so rock for coming here...Pulley Show this Friday!Hope we see us anytime !!!Ciao guys, happy new year!!Rock out to you guys Before Games and still Listen to Pulley while in My office!Finally I have Pulley on my friends list.You guys always seem to keep making great music.Not only are you a terrific punk band, but moreover simply a terrific and talented group that makes powerful music in general.Long live Pulley, man!Pulley and other bands has always been able 2 make me feel better about life.You got love in Tijuana dudes!!This is not a MySpace login page, please do not enter your MySpace login information (email address or password).Do you wish to continue your form submission?"Id + " Link: " + targetLink.Id + " Text: " + targetLink.Original Postings are made to tpulley.I'm writing, but things have been busy for me lately, not to mention mandatory fun time in the snow.After a little time googling I found getID3, a php class to extract useful info from a good variety of music and video formats.It even comes with some excellent sample code for using it in ways I specifically intend.Two days ago, I went with Tim to the nearby goodwill for fun and found something that filled me with a rush of nostalgia:"A Virtual Adventure Game Inspired by the Work of H.For me, this game was a lot more than just 1's and 0's clicking inside a machine (yes, some enjoyable games are exactly like that to me).Alone in the Dark was better to me for being more focused inside the mansion, not running around on the streets wondering where to go, and having the monsters appear infrequently (and all the more suspenseful!Oregon for the summers, and ended up deciding to stay here for high school.My hunger loses attention to other things I have going on, and that's been happening lately as I've been getting serious hours into the various projects I'm doing.Yesterday I ran up to king burrito on bike to pick up a sizable order for the whole house.King B is a pretty short ride, but I haven't been terribly active lately and I was very much needing some food in me.It was freezing but not really that cold, and there were hardly any cars out.Broadway was still closed by the time I got to the Steel Bridge and dinked around taking pictures (hilarious!Then I got a couple donuts at voodoo, and cruised around downtown before going back over the burnside bridge and into a donut shop by the plaid I had never been in before.They even searched the back and produced a ceramic mug for me when I asked.It wasn't windy, so it didn't feel very cold.There's been a decline in oil prices due to warm weather in the northeast US, leading to record market closings for the past few days now.The forums are active, and people are making all kinds of great songs for it.Sadly, no wii availability for it (yet?There is still snow on the ground, but not very much yet.TJ's choco truffles and spare cat litter for fixing the neighbor's laptop.That's not a comprehensive solution by any stretch, just ideas of which there are many.There are plenty of things that work right with schools and I can relate good experiences I've had, but it's not for everyone and there are plenty of people for whom school cannot provide the opportunities they truly need.It's an issue of public mindset, I suppose.I've been wanting for a long time.Dunno how many people will show up, but I imagine there being at least 6.Compared to freezers, I know a way to make ice efficiently and I want to construct an 'ice generator' to keep myself cool with solid ice like in olden times.Bonus points for integrating ice cooling into my car.Thank you for visiting our website.We hope that 2008 will be very prosperous for you.Most changes in the market will require changes in personal and business strategies to stay ahead of the curve.Website hosting, design,
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![DEVOTCHKAS : [1998] - Oi Toy EP](/covers/18/18127/alb_73241_th.jpg "DEVOTCHKAS : [1998] - Oi Toy EP")
