Skiers can increase their velocity during a downhill run on an undulating slope by using body motions to increase their kinetic energy . In a different context, an example of this phenomenon is the figure skater who, in a leaping pirouette, brings her outstretched arms in closer to her body, which increases her angular velocity and, hence, the kinetic energy of her system, so she accelerates through the pirouette in midair without ever touching the ice. So too a skier may increase his kinetic energy and acceleration during a turn or when he runs the troughs in a mogul field by pumping up and down with his legs to shift his center of mass. In effect, there is a reservoir of potential energy in the human body that the skier may convert to kinetic energy. We can analyze this energy-conversion process by using the physical principles associated with work and energy.
KeywordsKinetic Energy Angular Momentum Angular Velocity Body Motion Centrifugal Force
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