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# It's a COG Thing_e-book

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Our video Volume 1, Issue 1 Newsletter Date 2nd General Lyceum of Kamatero https://youtu.be/bD-783foJcs YOU TUBE Επιλέξτε το παραπάνω link για να δείτε το βίντεο που γυρίσαμε στην αίθουσα γυμναστικής του σχολείου και στο μάθημα της Φυσικής Αγωγής. Select the link above to see the video that we shot in the school gym hall during the physical education lesson.

Our Data Volume 1, Issue 1 Newsletter Date 2nd General Lyceum of Kamatero We took measurements of time. After lifting the feet off the floor and trying to balance without holding on to the chair with the hands, we measured the time the student can keep balance. Time of student’s balance (s) Without stretching out arms or legs 9:85 With stretching out arms or legs 15:84

The COG Volume 1, Issue 1 Newsletter Date 2ND GENERAL LYCEUM OF KAMATERO The definition: What Physics tells us 2nd General Lyceum of Kamatero Volume 1, Issue 1 Newsletter Date The center of gravity is a geometric property of any object. The center of gravity is the average location of the weight of an object. We can completely describe the motion of any object through space in terms of the translation of the center of gravity of the object from one place to another, and the rotation of the object about its center of gravity if it is free to rotate. If the object is confined to rotate about some other point, like a hinge, we can still describe its motion. Center Of Gravity (COG)

The COG Volume 1, Issue 1 Newsletter Date 2ND GENERAL LYCEUM OF KAMATERO The definition: What Physics tells us 2nd General Lyceum of Kamatero Volume 1, Issue 1 Newsletter Date The ability to locate the center of gravity of a body is based on the knowledge of what it takes for a system to be balanced, or in equilibrium. Two conditions must be met: 1. All the linear forces acting on the body must be balanced. Center Of Gravity 2. All the rotary forces (torques) must be balanced. Another way of expressing these necessary conditions for equilibrium is to say that the sum of all the forces acting on the body must equal zero. If there is a downward-directed linear force, there must be an equal upward force so that the vector sum of these forces equals zero. If there is a negative clockwise torque, it must be canceled out by a positive counterclockwise torque of equal magnitude.

The Core Volume 1, Issue 1 Newsletter Date 2nd General Lyceum 2ND GENERAL LYCEUM OF KAMATERO CORE-STABILITY- of Kamatero What Physical Education tells us Volume 1, Issue 1 TRAINING What Physical Education tells us Newsletter Date \"Tighten your core\" \"Strengthen your core\" - you hear the advice all the time. But what exactly is Core? Core is defined as the muscles of your deep muscular corset: Transverse abdominus (deepest ab muscle), diaphragm (a muscle that assists in breathing), multifidus (deep back muscle along spine), and pel- vic floor (helps to prevent urine flow). Many of the pain problems that we treat every day in our Physical Therapy department are related to imbalances in the “core”.

SPORTS SCIENCE STORIES Volume 1, Issue 1 Newsletter Date 2nd General Lyceum 1. THE ‘KORBUT FLIP’ of Kamatero WAS BANNED FROM THE OLYMPICS Olga Korbut - The Development of Modern Gymnastics  In the 1972 Olympics, Olga Korbut became the first gymnast to complete a back tuck on the balance beam, becoming an innovator in the sport. Her athletic ability and routines revolutionized gymnastics.  Before Olga Korbut, the skills performed on a balance beam were mostly dance, with few aerial or acrobatic elements.  Olga's innovation in gymnastics led to various evolutions in the balance beam. As gymnastics skills, such as the back tuck, became more difficult, the stress experienced by the gymnast increased. There was a need for balance beams to be more accommodating. Beams were then manufactured with springs inside of them Olga Korbut performed the move at the (information on why on the Balance Beam page!). Olga's worldwide fame brought the sport of 1972 Games. gymnastics to the forefront of the international sports world and inspired many young girls to join local What’s now called the Korbut flip, a back- gymnastics programs . ward somersault on the uneven bars, has been banned because it’s just too danger- ous. Volume 1, Issue 1 Newsletter Date 2 n d G e n e r a l L y c e u m o f Watch the video: https://www.youtube.com/watch?v=spAlIMm8jSg

SPORTS SCIENCE STORIES Volume 1, Issue 1 Newsletter Date 2nd General Lyceum 2. of Kamatero DICK FOSBURY HIGH JUMPING Dick Fosbury Changes The High Jump Forever There are two properties of the center of gravity that have a great impact on sport. First of all its location is dependent on the shape of the body. So if the same body is to take a different shape, the position of the center of gravity will shift. An athlete that bends his/her legs will lower his/her center of gravity position. This, amongst other things, will result in greater stability, something especially important in sports such as wrestling. Also, and this may sound the strangest, the center of gravity can lie entirely outside the body itself. For example, if the body is hollow it will literally be positioned somewhere in the air. During the Olympic Games in Mexico, in 1968, an, until then unknown athlete, the American Dick Fosbury, came from nowhere to teach the world about both of these properties. Mexico 1968 Olympics: One of the most memorable and historic The truly ingenious leap (!) in the technique was that by clearing the bar with his back and by changing the moments in Olympic history as Dick Fos- shape of his body, the athlete could clear the bar bury re-invents the high jump competition without his center of gravity having to also clear it. By this change in body shape he was able to move his with the use of his Fosbury flop method center of gravity outside his body. The energy required for a jump depends on the maximum height of the instead of the classic scissors technique. center of gravity and so by lowering its position one also lowers the energy required to clear the bar. Sport Science Stories 2017—2018 2 n d G e n e r a l L y c e u m o f K a m a t e r o Watch the video: https://www.youtube.com/watch?v=9SlVLyNixqU

SPORTS SCIENCE STORIES Volume 1, Issue 1 Newsletter Date 2nd General Lyceum 3. of Kamatero GRAND JETÉ The Illusion of Flight The grand jeté is a classic ballet maneuver in which a dancer executes a horizontal leap while moving her arms and legs up and then down. At the center of the leap, the arms and legs are gracefully extended. The goal of the leap is to create the illusion of flight. The center of mass- The goal of the grand jeté is to create the and hence the center or gravity--or an extended object illusion to the audience that the dancer is follows a parabolic trajectory when undergoing projectile floating through the air. From the moment motion. But when you watch a dancer leap through the of take off, to the instant of landing, the air, you don' t watch her center of gravity, you watch her dancer's center of gravity follows a para- head. If the translational mot ion of her head is bolic trajectory and thus the jump can be horizontal — not parabolic — this creates the illusion that seen as a projectile motion activity. How- she is flying through the air, held up by unseen forces. ever, unlike some projectile motion activi- Figure (b) illustrates how the dancer creates this illusion. ties, in which the shift from the upward While in the air, she changes the position of her center of phase and downward phase of the parab- gravity relative to her body by moving her arms and legs ola is extremely evident, in the grand jeté, up, then down. Her center or gravity moves in a there is an illusion created in which the parabolic path. but her head moves in a slraight line. It 's dancer's head seems to float horizontally not flight, but it will appear that way, at least for a at the highest point of the trajectory, be- moment. fore beginning the descent down. Sport Science Stories 2017—2018 2 n d G e n e r a l L y c e u m o f K a m a t e r o Watch the video: https://www.youtube.com/watch? v=nfy05cfY0qQ