Riders in the sledding occasions reach their quick speeds because of the conversion of gravitational prospective energy into kinetic energy. Gravitational prospective energy represents stored energy and increases as an object is raised farther from Earths surface. The possible energy is converted to another kind of energy once the item starts falling. Kinetic energy is the energy of motion. Both gravitational prospective energy and kinetic energy increase as weight boosts, suggesting there is more energy in a four-person bobsled team than there is in a one-person luge or skeleton for a given speed.
Bobsled, luge and skeleton professional athletes descend twisting, steep tracks at speeds up of 80 miles per hour (130 kmh).
Speed alone might be the factor that draws lots of sports fans to the bobsled, luge, and skeleton events at this years Beijing Winter Olympics. Underneath the thrilling descents of the winding, ice-covered track, a myriad of principles from physics are at play. It is how the athletes respond to the physics that eventually figures out the fastest runs from the rest of the pack.
Much of the enjoyment of a luge run is easy to miss– the athletes motions are often too small to observe as they fly by looking like nothing more than a blur on your tv. It would be simple to assume that the rivals are merely falling or moving down a track at the impulse of gravity.
Tracks for sliding events– like the Olympic track from the 2018 Pyeongchang Winter Olympics– drop hundreds of feet and feature lots of tight turns. Credit: Korean Culture and Information Service
Gravity and energy
Gravity is what powers the sleds down the ice-covered tracks in bobsled, luge and skeleton occasions. The big-picture physics is basic– begin at some height and after that fall to a lower height, letting gravity speed up professional athletes to speeds approaching 90 mph (145 kph).
This years races are happening at the Yanqing National Sliding Center. The track is approximately a mile long (1.6 km), drops 397 feet of elevation (121 meters)– with the steepest section being an extraordinary 18% grade– and comprises 16 curves.
Since of the conversion of gravitational potential energy into kinetic energy, riders in the sledding events reach their quick speeds. Gravitational potential energy represents kept energy and increases as an object is raised farther from Earths surface. The potential energy is transformed to another type of energy once the item starts falling. Kinetic energy is the energy of movement. If it strikes a window is that the ball transfers its kinetic energy to the glass, the reason a flying baseball will shatter the glass. Both gravitational possible energy and kinetic energy increase as weight increases, meaning there is more energy in a four-person bobsled group than there remains in a one-person luge or skeleton for a provided speed.
Racers are dealing with a lot of kinetic energy and strong forces. When professional athletes go into a turn at 80 miles per hour (129 kph) they experience accelerations that can reach five times that of normal gravitational velocity. Bobsled, luge and skeleton may look simple, in truth they are anything.
Racers need to be as aerodynamic as possible to reduce drag and go quicker.
Aerodynamics
Many tracks are around a mile long (1.6 km), and the athletes cover that distance in simply under a minute. Final times are calculated by including four runs together. The difference in between the gold medal and silver medal in the mens songs luge at the 2018 Winter Olympics was just 0.026 seconds. Even small errors made by the finest athletes in the world can cost a medal.
All the professional athletes start at the same height and decrease the same track. The distinction in between gold and a disappointing outcome comes not from gravity and prospective energy, but from a quick start, being as aerodynamic as possible and taking the fastest path down the track.
While gravity pulls the athletes and their sleds downhill, they are constantly clashing with air particles that develop a force called air drag, which presses back on the athletes and sleds in an instructions opposite to their speed. The more aerodynamic a professional athlete or group is, the higher the speed.
Bobsled groups should tuck themselves behind the leading edge of the sled to avoid the oncoming air.
To decrease drag from the air, luge riders– who are face up– lie as flat as possible. Downward-facing skeleton riders do the very same. Whether in a team of 2 or 4, bobsled riders remain tucked tightly inside the sled to lower the area available for air to smash into. Any body placing errors can make athletes less aerodynamic and lead to small increases in time that can cost them a medal. And these mistakes are difficult to fix at the high velocities and forces of a run.
The shortest way down
Besides being as aerodynamic as possible, the other major distinction between a quick and a slow run is the path riders take. If they lessen the overall length taken by their sleds and prevent zigzagging across the track, riders will cover less distance. In addition to just not needing to go as far to cross the goal, shortening the course suggests dealing with less drag from air and losing less speed from friction with the track.
Skeleton racers do not have a method of directly managing the runners, so they need to utilize subtle body movements to flex the sled and start turns.
Runners on luge sleds have curved bows at the front where riders position their calves. By moving their head and shoulders or flexing their calves, athletes can turn the luge. Skeleton riders do not have these controls and need to flex the sled itself utilizing their shoulders and knee to start a turn.
All of these subtle motions are difficult to see on television, however the repercussions can be large– oversteering may lead to collisions with the track wall or even crashes. Inappropriate steering might cause bad turns that cost riders time.
Though it may appear that the riders simply move down the icy track at excellent speeds after they start, there is a lot more going on. Audiences will have to pay attention to the professional athletes on those fast-moving sleds to discover the fascinating facets of physics in action.
Composed by John Eric Goff, Professor of Physics, University of Lynchburg.
This post was very first published in The Conversation.