The games in science today | how to “fly” ski jumping farther?
Dive, jump, fly, land, glide…Ski jumping comes from man’s most primitive desire to fly.Athletes can fly in the air for a few seconds without any external force, only with the help of the huge inertia brought by the platform. This kind of fleeting leap will bring great physical and mental pleasure to people.Song Qiwu of China competes in the men’s ski jumping team event at the Beijing Winter Olympic Games on February 14, 2008.Xinhua Feng Kaihua was taken at the winter Olympics, the Chinese diving platform ski team in both number and a project on record, although the results from the world’s top players still have a distance, but the 20-year-old starlet Song Qiwu believe, ski jumping athletes in China with the help of the “training” artifact wind tunnel laboratory, can fly farther.”Flying” ski jump is mainly divided into four stages, namely, assist stage, take-off stage, flight stage and landing stage.In the sliding stage, the athlete slides down from the starting point, and the gravitational potential energy is converted into kinetic energy. The greater the gravitational potential energy is, the more kinetic energy is converted.To reduce the impact of air resistance, competitors often squat and extend their arms back against their bodies, providing faster speed during the jump phase.In the jump phase and the flight phase, flying further becomes the ultimate goal of the competition.Because athletes can’t overcome the influence of gravity, so they will choose to your body and your skis as much as possible to keep the attitude of the parallel to the ground, the athletes take a body forward, ski forward separate V classic posture at the same time, it can increase the below contact with body surface area of the air, and you can also give the body of one of the most ideal Angle of attack,Like an airplane taking off, it maximizes the lift force of the air.Although this process lasts for a shorter time, the greater lift allows the athlete to protect the flight longer.From a height of 100 meters, without any protection, how can athletes land unscathed?For ski jumping, first, the take-off and landing slope of ski jumping are calculated, so that the athletes’ take-off and landing track is consistent with their parabolic trajectory, and it is not easy to land in a vertical way;Second, the landing surface is an inclined plane. The slope of the inclined plane breaks down the horizontal force, and the falling force and the landing slope force form an Angle, which converts the original downward impact force into the acceleration force on the slope. The athlete can land safely and continue to slide for a period of time, using the ground friction to stop and finally finish the race.To minimize damage from a fall, ski suits are usually made of synthetic fibers and lined with foam to cushion the impact of a fall.The skis are 11.5 centimeters wide at most and 1.46 times longer than their height, providing a good guarantee of stability when landing.Ski jumping, an event without world records, is a very wind-dependent event because the instantaneous wind and direction of the jump will affect the final jump distance.For example, when jumping against the wind, athletes are more likely to jump out of a longer distance with lift, so it is not necessarily the farther the jump, the higher the score will be, but the corresponding value should be added or subtracted according to the instantaneous wind direction and speed.In addition to wind speed, updrafts, crosswinds or cyclones can put athletes in the air at risk.To this end, Xueruyi has installed wind speed measuring devices at various locations on the track.Therefore, ski jumping events can only be judged on the basis of the athletes’ competitive conditions under the specific weather and venue conditions on the day of competition, and there is no horizontal comparison with the results of other times or other venues. There is no world record.In terms of distance flown, the best ski jump has been over 250 meters.Source: Popular Science Times author: Yu Xiang Editor: Wu Tong Review: Wang Fei final review: Chen Lei