How Airplanes Fly Please let me remind all of you--this material is copyrighted. Though partially funded by NASA, it is still a private site. Therefore, before using our materials in any form, electronic or otherwise, you need to ask permission. There are two ways to browse the site: (1) use the search button above to find specific materials using keywords; or, (2) go to specific headings like history, principles or careers at specific levels above and click on the button. Teachers may go directly to the Teachers' Guide from the For Teachers button above or site browse as in (1) and (2). Almost everyone today has flown in an airplane. Let us start by defining three descriptions of lift commonly used in textbooks and training manuals. The second description we will call the Popular Explanation which is based on the Bernoulli principle. The third description, which we are advocating here, we will call the Physical Description of lift. The popular explanation of lift Newton’s laws and lift Air has viscosity
Aaron Benitez | SIETE DEMONIOS DEL EMPRENDIMIENTO EN MÉXICO Demonio #1 NO ES LO MISMO NACER EN OAXACA Y EGRESAR DE LA UNAM QUE SER DE CALIFORNIA Y ESTUDIAR EN HARVARD. No lo es. Aún el prestigio de la UNAM, el ITESM, el ITAM, la Ibero y demás no es suficiente para acceder a un estatus de élite en la vanguardia del pensamiento filosófico y desarrollo tecnológico del mundo. Esto es así porque el mejor talento siempre va a atraer al mejor talento. Y si el mejor talento está en la Ivy League, es tan sólo normal que los egresados con proyección de nuestras universidades nacionales busquen posgrados en alguna de esas instituciones. En este momento no existe un CEO de una macro-empresa creada en México que no haya estudiado en el extranjero. Lo cual no es malo. Más que una cuestión de nacionalismo, es una cuestión del entorno. Pero las mejores del mundo viven fuera de nuestras fronteras. Tú, experto programador egresado con las mejores bendiciones, ¿en qué mundo quieres trabajar? Demonio #2 NUESTROS EMPRESARIOS MÁS EMBLEMÁTICOS NO INSPIRAN.
EXCLUSIVE: Paul Walker's close friend shares intimate, never before seen pictures of the actor who 'was more interested in being a good father and a good son than an actor' Friends Ronn Shikari and Vince Krause said Paul Walker talked to his family about quitting acting so he could see his daughter more often Described the actor as fiercely loyal to his friends and lacking in arrogance associated with celebrities Another friend Ricardo Miller was Walker's Brazilian jiu jitsu instructor for almost 10 yearsHe traveled with the actor to movie sets to help coordinate fight scenesMiller took candid photos of the actor during their time togetherHe told MailOnline that Walker cared more about being a good father and son than about being a movie star By Chris White Published: 22:02 GMT, 7 December 2013 | Updated: 20:32 GMT, 8 December 2013 ‘Fast and Furious’ star Paul Walker was due to give up acting this year, so he could spend more time with his daughter Meadow. This is according to two of his closest friends, Ronn Shikari and Vince Krause, who both live in Hawaii. They were introduced to Paul seven years ago through their mutual love of jiu-jitsu.
The Strange History of the Sunflower You may not think that there is much to know about the sunflower. After all, the plant is virtually everywhere. Yet it has something more than a simple, straightforward history and is more of a globe trotter than you may imagine. Its story has the historical and continental sweep of a Hollywood epic, from the pre-European Americas to Tsarist Russia and back again. Sunflowers originate from North America but would travel to the Old World and back – and back again - in their centuries old journey to become the plant we know today. It has been suggested that the sunflower was even domesticated before corn. Yet no one would have guessed what the future of the sunflower held – and the travels it would endure. As today, the sunflower seed was cracked and snacked on - something you can eat between meals without ruining your appetite - albeit a much healthier snack than many we eat today. Russia was awash with the giant flowers, growing over two million acres a year. That’s right.
- StumbleUpon Truly passionate sex beats obligatory makeup sex any day. Maybe men don't feel the difference, but we women do. We hate fighting—it makes us feel alienated, confused, and downright disappointed. But the next time we bite your head off, don't rush to pack up your CDs. You need to know what her fighting words mean. The Attention Fight Opening Volley: "We don't go out anymore." It Means: She's nostalgic. Battle Tactics: Once a month, surprise her with a real plan. What You Win: Dinner counts as foreplay. The Friends Fight Opening Volley: "What's with the morons in your fantasy baseball league, anyway?" It Means: She's questioning your judgment. Battle Tactics: When she disses your buds, it feels like a personal insult, because friends are directly tied to identity and ego. What You Win: Peace. The Money Fight Opening Volley: "Do you really need another gadget?" It Means: She's implying a lack of responsibility on your part. Battle Tactics: Schedule budget talks. The Intimacy Fight The Kids Fight
Khan Academy Our 'War' On Fat Was A Huge Mistake [GRAPHS] The “war” on saturated fat is the biggest mistake in the history of nutrition. As people have reduced their intake of animal fat and cholesterol, many serious diseases have gone up. We are now in the midst of worldwide pandemics of obesity, metabolic syndrome and type II diabetes. Studies conducted in the past few decades conclusively show that neither saturated fat nor dietary cholesterol cause harm in humans (1, 2, 3, 4). Scientists are now beginning to realize that the entire low-fat dogma was based on flawed studies that have since been thoroughly debunked. Here are 6 graphs that clearly show how incredibly damaging it has been to advise people to reduce their consumption of animal fat. 1. Data from: Hoenselaar R. Have you ever heard of the “French Paradox“? It is a phrase used to describe the seemingly “paradoxical” fact that French people have a low risk of heart disease, while eating a diet that is high in saturated fat. Thanks to Dr. 2. 3. Source: Brehm BJ, et al. 4. Source: Dr. 5. 6.
Fanfare fades as Apple rolls out its new line of iPhones Consumers looking for a way to measure how much excitement there is with the new iPhones that go on sale Friday may want to check out the TaskRabbit index. In recent Apple launches, busy consumers have turned to the San Francisco micro-job site to hire people to wait in line for the latest iPhone or iPad. Last year, 350 people were hired just in San Francisco and New York alone for the "line skipping" jobs. "This year, we've seen just over 250 people sign up to have a TaskRabbit wait in line for them in all of our 15 active markets combined," said TaskRabbit spokesman Johnny Brackett. The drop in the TaskRabbit index is just one indicator that the legendary enthusiasm among die-hard Apple fans is a bit damper this year for the new iPhone 5c and iPhone 5s. Wall Street analysts seem split on whether the new iPhones will set a record for first weekend sales, as each previous version has. Of course, consumers will have the final say this weekend. The wild card is China.
12 Items a Lady Should Keep in Her Purse- MotorCity Moxie - StumbleUpon Several years ago, I enjoyed purse shopping. I stayed with the fashionable handbags, purses, pocket-books or whatever you like to call it. As of late, purses have become burdensome. Oftentimes, they hurt my shoulder, and they turn into big hole for me to get lost in. Though a purse is meant to add some element of organization to my life, it’s usually the opposite. I do carry pursues. Baby wipes-These come in handy not only after a tinkle, but also to do a quick wipe down in the ladies room.Perfume-Not the entire bottle, just an aspirator will do. Fully charged phone- Keeping the phone charged is necessary in case of an emergency. What items do keep in your purse at all times? Get The Moxie Manifesto Your weekly To-Do Tactics to help you BE GOOD, LOOK GOOD and DO BETTER! It's free! I respect your email privacy.
Earth, Atmospheric, and Planetary Sciences | 12.409 Hands-On Astronomy: Observing Stars and Planets, Spring 2002