| For other uses, see Pendulum (disambiguation).An animation of a pendulum showing the velocity and acceleration vectors (v and A).When the pendulum is displaced from its place of rest, the restoring force will cause the pendulum to oscillate about the equilibrium position.In other words, a weight attached to a string swings back and forth.The regular motion of pendula can be used for time keeping, and pendula are used to regulate pendulum clocks.History
2 Basic principles
2.Use for measurement
4 Other applications
4.Its function was to sway and activate a series of levers after being disturbed by the tremor of an earthquake far away.An Egyptian scholar, Ibn Yunus, is known to have described an early pendulum in the 10th century.Among his scientific studies, Galileo Galilei performed a number of observations of all the properties of pendula.His interest in pendula may have been sparked by looking at the swinging motion of a chandelier in the Pisa cathedral.He began serious studies of the pendulum around 1602.Galileo noticed that period of the pendulum is independent of the bob mass or the amplitude of the swing.The isochronism of the pendulum suggested a practical application for use as a metronome to aid musical students, and possibly for use in a clock.Perhaps based upon the ideas of Galileo, in 1656 the Dutch scientist Christiaan Huygens patented a mechanical clock that employed a pendulum to regulate the movement.Following an illness, in 1665 Huygens made a curious observation about pendulum clocks.Sciences expedition to Cayenne, French Guiana in 1671, Jean Richer demonstrated that the periodicity of a pendulum was slower at Cayenne than at Paris.From this he deduced that the force of gravity was lower at Cayenne.Huygens reasoned that the centripetal force of the Earth's rotation modified the weight of the pendulum bob based on the latitude of the observer.Christian Huygens published his theory of the pendulum.He demonstrated that for an object to descend down a curve under gravity in the same time interval, regardless of the starting point, it must follow a cycloid (rather than the circular arc of a pendulum).This confirmed the earlier observation by Marin Mersenne that the period of a pendulum does vary with amplitude, and that Galileo's observation was accurate only for small swings in the neighborhood of the center line.The English scientist Robert Hooke devised the conical pendulum, consisting of a pendulum that is free to swing in both directions.By analyzing the circular movements of the pendulum bob, he used it to analyze the orbital motions of the planets.Hooke would suggest to Isaac Newton in 1679 that the components of orbital motion consisted of inertial motion along a tangent direction plus an attractive motion in the radial direction.Robert Hooke was also responsible for suggesting (as early as 1666) that the pendulum could be used to measure the force of gravity.To Foucault, the precession was most easily explained by the rotation of the Earth.Riefler Clock from 1904 until 1929.This pendulum clock maintained an accuracy of a few hundredths of a second per day.Amplification of period factor of a pendulum for growing angular amplitude.The period of a simple pendulum is significantly affected only by its length and the acceleration of gravity.The period of motion is independent of the mass of the bob or the angle at which the arm hangs at the moment of release.The period of the pendulum is the time taken for two swings (left to right and back again) of the pendulum.For larger amplitudes, the velocity of the pendulum can be derived for any point in its arc by observing that the total energy of the system is conserved.Although, in a practical sense, the energy can slowly decline due to friction at the hinge and atmospheric drag.Thus the sum of the potential energy of bob at some height above the equilibrium position, plus the kinetic energy of the moving bob at that point, is equal to the total energy.Physical pendulum
The simple pendulum assumes that the rod is massless and the bob has negligible angular momentum in itself.It turns out that a physical pendulum behaves like a simple pendulum but the expression for the period is modified.Double pendulum
A more complex example is the double pendulum.This consists of a pendulum attached to the free end of another pendulum.Unlike a simple pendulum, the behavior of this system is much more complex.As the angles increase, however, the double pendulum exhibits chaotic motion that is sensitive to the initial conditions.Use for measurement
The most widespread application is for timekeeping.Clocks that keep time with the use of pendula lose accuracy due to friction.Pendulums are also widely used as metronomes for pianists.The presence of g as a variable in the periodicity equation for a pendulum means that the frequency is different at various locations on Earth.The pendulum can therefore be used in gravimetry to measure the local gravity at any point on the surface of the Earth.The bob of the pendulum does not move when its mounting does and the difference in the movements is recorded on a drum chart.Schuler tuning
As first explained by Maximilian Schuler in his classic 1923 paper, a pendulum whose period exactly equals the orbital period of a hypothetical satellite orbiting just above the surface of the earth (about 84 minutes) will tend to remain pointing at the center of the earth when its support is suddenly displaced.This is the basic principle of Schuler tuning that must be included in the design of any inertial guidance system that will be operated near the earth, such as in ships and aircraft.Coupled pendula
Two coupled pendula form a double pendulum.Many physical systems can be mathematically described as coupled pendula.Under certain conditions these systems can also demonstrate chaotic motion.Religious practice
Pendulum motion appears in religious ceremonies as well.The swinging incense burner called a censer, also known as a thurible, is an example of a pendulum.Pendulum clock
Simple harmonic motion
Conical pendulum
Spherical pendulum
Double pendulum
Foucault pendulum
Kater's pendulum
Harmonograph (a.Piero Ariotti (Winter, 1968)."Galileo on the Isochrony of the Pendulum", Isis 59 (4), p.University of St Andrews."Ibn Yunus and the pendulum: a history of errors".Toon, John (September 8, 2000).Charting the Globe and Tracking the Heavens: Navigation and the Sciences in the Early Modern Era.The constellation of Horologium was later named in honor of this book.Christian Huygens: The Measurement of Time and of Longitude at Sea."Hooke and Newton: Divining Planetary Motions".Physics Today 57 (2): 13.An interesting simulation of thurible motion can be found at this site.Matthews, Arthur Stinner, Colin F.The Pendulum: Scientific, Historical, Philosophical and Educational Perspectives.The Pendulum: Its Place in Science, Culture and Pedagogy.Science and Civilization in China: Volume 3, Mathematics and the Sciences of the Heavens and the Earth.Taipei: Caves Books, Ltd.This page was last modified 20:08, 10 January 2008.All text is available under the terms of the GNU Free Documentation License.Pendulum live at the Electric Ballroom in London during their 2007 tour.Pendulum are a drum and bass group originally hailing from Perth, Australia.In 2003, they relocated to the United Kingdom.The group comprises Rob Swire, Gareth McGrillen, Ben Mount (MC Verse) and Paul Harding.The Pendulum sound is typically heavy beats accompanied by low, buzzing basslines, overlaid with synthesized leads."Voodoo People" by The Prodigy.Pendulum have also been remixed themselves.In 2006, 'Painkiller' with the Freestylers was remixed by NOISIA and released on Against the Grain records."Slam" was also featured in the soundtrack for the video game MotorStorm on the Playstation 3 console.Written by Pendulum
4.Mixed by Pendulum
4.In 2005 they released their debut album, Hold Your Colour.In addition, it was one of the biggest selling drum and bass releases of all time.Pendulum have also collaborated with the Freestylers, releasing the single Fasten Your Seatbelt.MC Spyda and Tenor Fly also feature as vocalists on the song "Tarantula".At recent Pendulum DJ sets in Epsom and also Warwick University Student Union, it was announced that their new album would be available at the start of November 2007.However, it was later announced on BBC Radio 1, that the album was to be released Q1 2008 during a phone interview with a member of Pendulum.The new album, titled In Silico, has an official release date of 17th March 2008.Gareth McGrillen live at Carling Academy Newcastle in 2007.Their first performance was at the Fabric nightclub in London on 6 October 2006 accompanied by MC Jakes.On New Years Eve 2006 they headlined at Belvoir Amphitheatre in their home town of Perth, Western Australia, playing to a full house (around 6,000 people) alongside various international and local DJs.Pendulum did an extensive UK Tour sporting the full band accompanied by MC; Ben The Verse.Their performance at Electric Ballroom in London on the 28th of November was recorded and directed by acclaimed live music director Matt Askem.Mixed by Pendulum
Junglesound Vol.Jungle Sound Gold (2006): This album was not endorsed by Pendulum.Mixes
Pendulum Essential Mix (2005) Mixed for BBC Radio One.Jump N Twist, Pendulum vs The Freestylers feat.Pendulum at All Music Guide.Pendulum (Live) UK Tour.Pendulum Broadcasted on Sunday 18th September, 2005.Pendulum related images pulled from our Flickr group.Pendulum (Live) UK Tour
Only two dates left!Pendulum Discussion Forums are better than ever.Tandy suffers from bipolar disorder and though her poetry in this book focuses on spirituality, she covers other subjects as well, including poems about her psychiatrist, psychologist and children.Here are a few excerpts: Nancy, Psychiatrist Though I've known her just a year I come to her with no fear because her questions pertain to not just how are you mentally, but where your life is leading actually.Now new research is showing that routine sleep schedules can actually be beneficial to the outcomes of bipolar disorder.We recently covered a study which found that children suffering from bipolar disorder are more likely to misread facial expressions and experience certain moods such as irritability and excessive happiness.Now a new study, published in last month's issue of The Journal of Neuropsychiatry and Clinical Neurosciences, finds that the adults suffering from bipolar disorder are also prone to impaired emotional perception.For the study, 19 patients suffering from bipolar disorder I and in remission were compared to 22 healthy individuals (both groups were matched for age, gender, education, etc.The participants were all given an Affective Prosody Test
Read full story...Depressive Illness: Bipolar Disorders and Recurrent Depression, 2nd Edition.Oxford University Press, USA.Depressive Illness: Bipolar Disorders and Recurrent Depression, Second Edition, by Frederick K.Goodwin and Kay Redfield Jamison is finally in stores.The goal of the study was to examine the course of bipolar disorder during pregnancy.Johns Hopkins University, Department of Psychiatry and the National Institute of Mental Health have teamed together to create a new, innovative and free database, which researchers are saying is going to increase their ability to pinpoint genes linked to bipolar disorder.The database, called The Bipolar Disorder Phenome Database, is revolutionary in its ability to offer "...Because DNA samples are available for this group, the database will let researchers correlate specific symptoms with sequences of genetic material.UK shows that people who suffer from bipolar disorder and who also have a family history of suicide, may be at a higher risk for committing suicide themselves.Specifically, bipolar patients with a family history of suicide are three times more likely to attempt suicide than is the rest of the population.Eduard Vieta, one of the study's authors states, a family history of suicide also increases the risk of suicide for people who suffer from other mental illnesses.He's
Read full story...Recently, researchers at the University of Colorado discussed current research supporting this past research on bipolar disorder.Bipolar disorder is "a highly recurrent and debilitating illness."The illness typically requires lifelong treatment, and researchers have been studying which medications are the most effective.Participants in each study must be ages 18 to
Read full story...The reason for their fear seems mainly to be stigma associated with the disorder.Researchers state that studies
Read full story...Recently, we've covered stories on bipolar disorder in youth.With the rise in the number of teens diagnosed, it's important to know what signs to look for.Tribune points out, knowing the signs may not be enough.The problem is that many parents notice abnormal behavior in their children but chalk it up to an "adolescent or teenage phase" that will pass.The book was first published in 2005.Depression and Bipolar Disorder Chapter
Read full story...Both were published in the September 2007 issue of the American Journal of Psychiatry.BD participants who experienced manic symptoms while also in the midst of a depressive episode, those who received antidepressant medication along with a mood stabilizer recovered no faster than those who received a mood stabilizer plus placebo (sugar pill).One of the goals of our web site is to educate people about what living with bipolar disorder is like.AstraZeneca Pharmaceuticals wants to help you tell that story...Contest Guidelines 2007 WHAT: As part of the 2007
Read full story...The cause of these increases is unclear.Many experts theorize that the jump reflects that doctors are more expansively applying the diagnosis to children, and don't believe that the incidence of the disorder has increased."From a developmental point of
Read full story...Daughters of Madness is a new book on daughter's experiences of growing up with mentally ill mothers.The book is unique in that it includes an introduction on how children are affected by mentally ill parents and also covers the related research.Susan Nathiel, the author, is an accomplished psychotherapist who is also a
Read full story...With funding from the MBF Foundation and Beyond Blue, a team led by the Mental Health Research Institute of Victoria has developed an innovative structured group program to help people with bipolar disorder to better manage their condition.Sister Leslie has brought the Bipolar Planet out of the backwaters of the Web.These pages are not a substitute for consultation with your counselor, therapist, doctor, or psychiatrist.Pendulum Resources and by the authors.Home:
Support
Support
Welcome to the Pendulum Resources Support page.Pendulum Resources Forums
are a gathering place for bipolars and their friends and family.The information at this web site is for consumers, family members and mental health workers to make informed decisions about the care and treatment of bipolar disorder, AKA manic depression.These pages are not a substitute for consultation with your counselor, therapist, doctor, or psychiatrist.Pendulum Resources and by the authors."Are you sure you want to block this user?CLICK HERE TO BUY DRM FREE DOWNLOAD NOW!CLICK HERE TO BUY DOWNLOAD FROM ITUNES NOW!BBC Radio 1, all whilst continuing to tour the world over as DJs...The last 12 months have seen Pendulum retreat to the depths of the underground to work on their second album, and to hone and perfect their sound for the live arena.Led Zeppelin, a crunked up Soundgarden, Tool meets Timbaland, combined with the synthetic aggression and sonic purity of the original Pendulum sound.So apart from that, what the hell are Pendulum all about?In the words of the boys themselves...It felt like the same energy found with bands like Led Zeppelin and even The Beatles, and still occasionally today with bands like Tool, The Mars Volta, Queens Of The Stone Age and others.To us, it made perfect sense to combine the best of both worlds, but it had to be done in a way that didn't make it sound obvious.We want to hear something different and exciting, but the material we want to hear isn't getting made.BlogEntry td a:visited,
table."Are you sure you want to delete this comment?"Much appreciatedLove your sound!Yo fans of pendulum.Also check out propane the next single.WE HAVE BEEN NOMINATED FOR LOADS OF AWARDS THIS YEAR ATWWW.Yo fans of pendulum.Also check out propane the next single.Beigne A Nez de la part des marauds!COLD (11 songs) on stores since 11.SEE ALSO myspace and buy there.Cheers 4 the add, keep the tunes comin!!!Any pendulum fans come check out our stuff, kinda pendulum fused with klaxons!HURRY UP AND RELEASE IN SILICO!NEED A NEW FIX OF PENDULUM :D.If they dnt like it, they can fuck off.All I know is you guys are awesome, you rock live, and you created the perfect moment for me to ask out my current girlfried properly hahahaha.Thanks for the connection!!In Ukraine Pendulum it is considered the best dnb band.Mmm, your music is the definition of incredible.Thanks alot for the add guys!Your music is off the freakin chain!"Urgent Security Alert","Warning: You are submitting information to an outside site.This could be an attempt to steal your username and password.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.It is a resonant system with a single resonant frequency.Enter data for two of the variables and then click on the active text for the third variable to calculate it.This expression for period is reasonably accurate
for angles of a few degrees, but the treatment of
the large amplitude pendulum is much more
complex.If the rod is not of negligible mass, then it must be treated as a physical pendulum.Period of Simple Pendulum
A point mass hanging on a massless string is an idealized example of a simple pendulum.Succeed in Physical Science.Ron Kurtus (revised 13 November 2006)
A pendulum consists of a weight suspended on a rod, string or wire.When the weight or bob is moved and let go, the pendulum will swing back and forth in a regular
periodic motion.The affect of gravity on the bob results in the periodic motion and its length
determines the frequency of its swing.Pendulums have been used in clocks for hundreds
of years, because the motion is so regular.What are some properties of a pendulum?What is a demonstration of a pendulum in action?What are some applications of a pendulum?It takes a few seconds for the sound to start.When pulled to the side and let go,
the bob will swing down due to the affect of gravity.Also, the frequency is independent of the mass of the bob.You can click the Start button to set it in motion.Enter 2 to double the length.Sorry, you need JavaScript activated to use this Flash animation.When a pendulum moves, there is some air resistance on the bob and rod or wire.These forces are called damping forces.There is a slight damping factor included in the simulation.The two major applications of pendulums are in telling time and the Foucault Pendulum.This is still seen in the older grandfather clocks.Every time the pendulum goes back and forth, it moves a gear one notch.The length of the pendulum can be adjusted slightly, if the clock is running too fast or slow.Another interesting application is called the Foucault Pendulum.Earth has rotated under the pendulum.Pantheon in Paris, France.Earth that is revolving underneath the pendulum.Pendulums have been used in clocks for hundreds of years, because the motion is so regular.You know your pendulums.""Good try, but not right.Note: Your browser must be able to use JavaScript for this quiz to function properly.What happens when you double the mass of the pendulum bob?What happens if you decrease the length of the pendulum rod?How does a pendulum on the Moon compare with one on Earth?If you had problems, you had better look over the material again.Also, tell a friend about this material.Where can you go from here? |
