Spinning ring on a table found to behave more like a boomerang

first_img(Phys.org)—A trio of researchers, two with the University of California, the third with Sharif University of Technology, in Iran, has found that a common ring, such as is worn on the finger, spins differently on a tabletop than does a coin. In their paper published in Physical Review E, Mir Abbas Jalali, Milad Sarebangholi and Reza Alam describe their tests and observations and offer a theory on why a spinning ring behaves the way it does. Explore further © 2015 Phys.org If you use your fingers to spin a coin on a tabletop, it will tend to move around on the table in the same direction that it is spinning until it stops. That is not the case with a spinning ring, the researchers found (first by simply noticing it and then via testing). Unlike the movement of the coin, the ring will move first in the direction of its spin, but then will stop moving and reverse itself, moving against its own spin.A coin, the researchers note, tends to spin in the same direction as its spin due to friction—and that appears to be the case with a ring as well. Both also, at least initially spin atop a thin layer of air that gets trapped beneath one of its edge and the tabletop. But, because the ring, which is essentially the same thing as a coin except for the large hole in it, has that hole, the trapped air can escape. When it does, the researchers theorize, the frictional forces change, resulting in the ring stopping and changing directions.Intrigued by the odd movement of the spinning ring, and surprised that they could not find any description or study of it in the literature, the researchers set about studying the phenomenon in their lab. They created coins by cutting metal rods and rings by cutting metal tubes, both of a variety of different sizes and thicknesses and then set them to spinning while recording with a high-speed camera. Citation: Spinning ring on a table found to behave more like a boomerang than a coin (2015, September 25) retrieved 18 August 2019 from https://phys.org/news/2015-09-table-boomerang-coin.html Moons in hiding More information: Terminal retrograde turn of rolling rings, Phys. Rev. E 92, 032913 – Published 22 September 2015 , dx.doi.org/10.1103/PhysRevE.92.032913 . On Arxiv: arxiv.org/abs/1412.1852ABSTRACTWe report an unexpected reverse spiral turn in the final stage of the motion of rolling rings. It is well known that spinning disks rotate in the same direction of their initial spin until they stop. While a spinning ring starts its motion with a kinematics similar to disks, i.e., moving along a cycloidal path prograde with the direction of its rigid body rotation, the mean trajectory of its center of mass later develops an inflection point so that the ring makes a spiral turn and revolves in a retrograde direction around a new center. Using high speed imaging and numerical simulations of models featuring a rolling rigid body, we show that the hollow geometry of a ring tunes the rotational air drag resistance so that the frictional force at the contact point with the ground changes its direction at the inflection point and puts the ring on a retrograde spiral trajectory. Our findings have potential applications in designing topologically new surface-effect flying objects capable of performing complex reorientation and translational maneuvers.center_img This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Credit: M. A. Jalali et al., Phys. Rev. E (2015) Supplementary video from the paper “Terminal retrograde turn of rolling rings” authored by Mir Abbas Jalali, Milad S. Sarebangholi, and Mohammad-Reza Alam, published in Phys. Rev. E 92, 032913 – Published 22 September 2015 In studying the video, it became apparent to the researchers that the change in direction came about due to the change in air flow. They also discovered that the reverse-effect occurred with all of the rings they tested, suggesting the behavior is both consistent and replicable, traits they suggest, that might be useful when designing objects that move on topologically flat surfaces, especially those that require complicated reorientations or automatic reversals. Journal information: Physical Review Letters , arXivlast_img read more

Releasing Resurgent India

first_imgThe book, launched in the presence of the Minister of Petroleum & Environment Veerappa Moily is an endeavour to discover the true significance of the contributions of Rajiv Gandhi in different areas of national life.Talking about the prime subject of his book, PDT Achary said, ‘Rajiv Gandhi is perhaps one of the most misunderstood prime ministers in Indian history. It is important to first understand the heart and mind of one of the nation’s most influential leaders in order to be able to understand his ambitious policies in their entirety. Rajiv was clearly a man ahead of his time. While we are still living in a time period of five-year plans, his policies envisioned two decades. I hope I have been able to capture the essence of his futuristic vision and provide a balanced perspective of the media trial that he underwent during his tenure.’ Also Read – ‘Playing Jojo was emotionally exhausting’This book objectively evaluates the contributions made by Rajiv Gandhi towards the nation. The prologue takes us through the major phases in Indian history and highlights the continuity of its cultural and political traditions, beginning from the Indus Valley Civilization to the later part of the 20th century. The epilogue narrates the post-1989 political developments characterized by instability caused by the coming and going of governments in quick succession and the assassination of Rajiv Gandhi. It also provides a perspective on his personality and performance and also on the implications of his death for the political future of India.Commenting on the book, Hamid Ansari said, ‘To write about Rajiv Gandhi, a modern Indian and his attempt to give a new thrust to a traditional India, would not have been easy. He had a vision of global peace and was one of the firsts to discuss about nuclear disarmament. I hope this book will be read by all those who are interested in contemporary Indian politics.’last_img read more

Sticking along in a bad marriage is wrong

first_imgPublishers believe pretty faces sell more books. Which is why the author picture on the back cover is paid more attention to at times than the content of a book. Which is not to say Shruti Sharma’s debut novel Abyss to Abyss is not interesting between the covers. It’s a good-hearted story of a girl stuck in a bad marriage who still believes in the power of dreams. Millennium Post had a quick tête-à-tête with Sharma. Read on…This being your debut book, how much of you is in protagonist Ria? Most writers end up making their first book autobiographical. Also Read – ‘Playing Jojo was emotionally exhausting’This book is a work of fiction. But I think there is a little bit of Ria in all of us. Her character is very real, she does stupid things, she has fears like any one of us, she cries, she gets excited,  she has her gloomy moments. At the same time she also embodies someone who has the courage to go  beyond the boundaries, yes she is scared but she challenges herself and dares to explore the unknown which I think is admirable and inspiring.  Ria goes through an arranged marriage and moves to US with a stranger. You live abroad. How prevalent is arranged marriage among NRIs today? Also Read – Leslie doing new comedy special with NetflixI think it’s very common for guys here to get married to girls from India. In general, it’s so common for professionals here to just fly to India for 15 days, meet girls and then just marry one of them.  I live in Silicon Valley and most Indian girls that I have met here were here because of  arranged marriage. Here is the sad part, not many are happily married. And even more sad? No one talks about it. They choose to live through it because they are scared. And I think a lot of  this is cultural. It’s embedded subconsciously that once you are married you got to make it work…which is twisted because people should not be together if they are not meant to be together.  I am not saying that all the marriages that are arranged are bad, what I am saying is that not very often do the girls (in bad marriages) take a decision of saying ‘You know what I am not going to put up with this crap anymore.’ In this novel, Ria recognises that sticking along in a bad marriage is wrong. And in the end everything turns out just fine and that’s the message I wanted to  convey. That people in bad marriages should not think that it’s the end. Pursue your dreams what may be…The universe guides you.Every character in my book is telling a story and it has a deeper meaning.  Ria seems to be all good. Do you think you could have painted her a little more grey?I think she does a lot of ‘wrong’. She does her fair share of ‘stupid’ things. She kept thinking her husband Jay would change then she chased Tanishq in desperate hope to find love so she wasn’t all that good. I painted her naive, that’s a color too. What prompted you to write a book?I grew up seeing my mom who has authored many books and I always wanted to write one. The timing was just right, professionally I had met all my goals so I thought of pursuing my long time dream of writing a novel. Why an e-book? There are takers for ebooks in the West, in India it is trend yet to catch upPaperback is also available through Amazon , Author House website and Barnes & Noble. Right now my publisher told me that the distribution channels (US based) will be able to sell the books internationally as well. Link: http://amzn.to/1sRRfZ8 What next for you? Plot of the next book in mind?Next book? I have a story in my mind but it’s very embryonic, again it’s going to be the one that can leave some sort of a message in the hearts of those who read the book. Did you have a specific readership in mind when you started writing?Mostly everyone but I think girls, who have been or are going through a rough relationship/ marriage will be able to relate to it. I hope this story can inspire people.last_img read more

Punjabi funny bone

first_imgBehroopiya Entertainers presented Saanu Kee, a 60 minute Punjabi Standup Comedy with  Amit Tandon and Maheep Singh, two comedians born at the same hospital in the same city but to different parents and separated by their fate. Finally, they were reunited by their sense of humour. Both of them believe that anything once translated to Punjabi sounds funny. So, this is the first stand-up comedy in Punjabi that has easily understandable Punjabi fun and catch phrases.  Also Read – ‘Playing Jojo was emotionally exhausting’Saanu Kee is one of the most commonly used Punjabi terms applicable in almost all situations. Amit Tandon, has done more than 500 stage performances across a number of cities. He is the one who conceptualized as well as hosts the Grandmasters of Comedy one of the most popular and longest running comedy nights in the country. Maheep Singh, is commonly called ‘The Gujarati Sardar’. He began doing stand-up comedy as an exercise to come out of depression and now he is tickling the funny bones of the audience regularly. One of the most interesting aspects of his performance is that he states facts.last_img read more

Doctor nursing home asked to pay Rs 20L as compensation

first_imgKolkata: State Consumer Disputes Redressal Commission has directed Roy Nursing Home in West Midnapore and a doctor to pay Rs 20 lakh as compensation to the family members of a patient who died of medical negligence.The incident took place in November 2013 when the victim, Banamali Samanata, was taken to Dr T K Biswas, a local doctor from Rabindra Nagar in the same district after he complained of severe abdominal pain. A resident of Barmunibgarh village under Kharagpur police station, Samanta was asked to take admission to Roy Nursing Home. After the patient was admitted to the nursing home under Dr Biswas, various clinical tests were performed on him. Medical tests confirmed that the patient had gallbladder stone and CBD stone as well. Dr Biswas conducted a surgery on the 59-year-old patient at the nursing home. Following the surgery, the patient started vomiting and also complained of respiratory problems. Also Read – Rain batters Kolkata, cripples normal lifeThe family members of the patient informed the doctors about the deterioration of his health condition. The doctor told the family members that this was nothing unusual and his condition would improve in the next few days. Prasenjit Samanta, the victim’s son, said the patient was released from the nursing home on November 14 after which he developed serious complications. He complained of severe respiratory distress accompanied by vomiting. When his family tried to readmit him to that nursing home for the second time, admission was denied. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedOn November 16, the family members rushed him to Midnapore Medical College and Hospital where USG and several others tests revealed that the CBD stone had not been removed then and the patient had already developed sepsis due to lack of proper treatment. The patient was later shifted to a private hospital near EM Bypass where another surgery was conducted. The efforts went in vain as he died of sepsis on December 10. The patient’s family later started a case with the State Consumer Disputes Redressal Commission (SCDRC) in September 2014.last_img read more

Day in day out

first_imgShowcasing perceptions‘Silence of the Heavens’, a solo art exhibition by Mamoon Nomani, Jamia Millia Islamia, will showcase a series of paintings at Lalit Kala Academy where the dynamics of different geometric shapes will be explored. The art exhibition will showcase works that has come out of his decade-long patience. The artist’s use of forms often creates optical illusions that trickily present altered perceptions, playing with the dimensions of weight, height and perspective. Also Read – ‘Playing Jojo was emotionally exhausting’When: February 29 to March 6Where: Lalit Kala Academy, Gallery No 3, Rabindra Bhawan Timings:11 am till 7 pmWhen one uses imageryWARP ‘N WEFT- a painting exhibition will be held in India Habitat Centre. Ritu Chopra’s exhibition consists of artworks in abstract genre, based on Kabir’s verse, ‘Jhini, jhini bhini chadariya’ wherein Kabir talks of the body as the cloth spun by God, having the subtle energy channels, the ingla and pingla as the warp and weft. Ritu is so inspired by Kabir’s simple couplets that she had, in the past, painted a series using figurative imagery. There is strength of form and balance of composition in her current works. She uses the related relevant chromatic hues in each artwork. There will be around 30 artworks on display. Also Read – Leslie doing new comedy special with NetflixWhen: March 16-24 Where: Palm Court, India Habitat Centre Timings: 10 am to 8 pmIndulging in fashionSahachari Foundation Events is going to organise ‘Design One 2016’- an exhibition with a specially curated list of designers, who will exhibit their work in the national Capital. The exhibition’s objective is to support charities, with this years’ partner Shine Home for Women. The exhibition will feature a combination of carefully selected established and budding designers, which includes famed couturieres Abu Jani and Sandeep Khosla, Akaaro by Gaurav Jai Gupta, Nidhi Tholia, Vogue Fashion Fund winner Pero By Aneeth Arora and many others.  When: March 3-4Where: The Grand, Vasant KunjTimings: 11 am to 8 pmTribute to women12th edition of IAWRT Asia Women’s Film Festival will be held in the national Capital where different films will be screened. The festival will showcase the work of women filmmakers of Asian origin bringing a rich and diverse collection of films from 13 countries including Bangladesh, India, Israel, Myanmar, Philippines, Portugal, South Korea, Syria, Taiwan, Turkey, U.K., USA and Vietnam. The festival includes a selection of 47 films and sound works; a seminar and an exhibition. Screenings will be followed by discussions with directors present.When: March 3-5Where: India International Centre, Max Mueller MargTimings: 9:30 am onwards.Magic of PoetryAll the lovers of Urdu poetry in the national Capital can come together to relish their favourite genre as  Shankar Lall Murli Dhar Memorial society is going to host the 51st edition of Bazm-e-Mushaira in the memory of Late Shankar lall ‘Shankar’ and Late Lala Murli Dhar ‘Shad.’ Mushaira will act as a thread to the most unpredictable relationship that is the trademark of India and Pakistan, which transcends all boundaries and creates an unbelievable bonhomie amongst poets from both sides.When: March 5Where: Modern School, Barakhamba RoadTimings: 8pm onwardslast_img read more

Kolkatans start thronging Park Street as Christmas mood sets in

first_imgKolkata: With the Chief Minister Mamata Banerjee inaugurating the Christmas Festival on 21 December, people started visiting Park Street in large numbers from Sunday afternoon to soak in the spirit of the festival.Park Street has become the destination of Christmas revellers in the city and the area has been suitably decked up to host the grand festival. The entire stretch of Park Street has been illuminated and the Christmas Carnival has rolled out in its full glory. The event will continue till 30 December. Also Read – Rain batters Kolkata, cripples normal lifeThe festival was thrown open to the public after the Chief Minister inaugurated the festival at Allen Park on Friday. This has become an important event in the year-end calendar of Kolkata. City dwellers thronged Park Street and its adjoining areas and enjoyed the lighting and decorations. The special attraction of the Christmas Festival this year will be the performances from buskers in and around Park Street and Camac Street crossing. The programme would be held on the day of Christmas between 4 pm and 10 pm. The state Information and Cultural Affairs department will organise various cultural programmes at Allen Park during the festive days. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedPeople stood in queues outside various bakery stalls in the New Market area on Sunday to buy cakes. Various tourist attractions in the city like Alipore Zoo, Victoria Memorial, Science City and Eco Park witnessed large footfalls on Sunday. It may be mentioned that the Christmas Festival at Park Street and its festive fervour draws a large number of foreign tourists as well and the state Tourism department is hopeful that the number will increase further this year. Adequate security measures have already been taken by the city police along Park Street and other areas, which see large footfalls during Christmas and New Year. Watchtowers have been set up at various points to maintain surveillance. There will be additional police personnel deployed at various places in the city during Christmas. Additional policemen have been deployed at Park Street and its adjoining areas to avoid any untoward incident. The entire stretch of Park Street has been divided into two flanks by placing security barricades in the middle of the road. All the vehicles would be diverted through alternate routes during Christmas. On the occasion of Christmas Festival, the state for the first time is going to illuminate seven churches in the state in Darjeeling, Kalimpong, Kurseong, Jalpaiguri, Bandel, Chandannagore and Krishnanagar. There will also be a cultural programme at Chandannagore church from December 26 to 28.last_img read more