Circular Motion in Gymnastics by Diana Adele Greis
Honorable - Contrived Category
School: Centerville High School
Teacher: Raquel VonHandorf
This contrived photo shows a gymnast performing what is called a ?giant? in gymnastics. An object in circular motion moves at a constant speed with a fixed radius. Because the gymnast?s height is constant, the radius of the circle she makes from her toes to her hands on the bar is also constant. As the gymnast approaches the downward position, the potential energy decreases, and she picks up speed through kinetic energy. As she starts moving back up in the rotation, kinetic energy will decrease, and a force is needed to continue the rotation. The gymnast?s body is mapped out like a motion diagram; the camera captures more pictures at the top of the giant because she is slowing down and vice versa picking up speed at the bottom. Arching her body and bending her knees just slightly moves the center of mass closer to the bar. This provides the kinetic energy to get her around the bar. Her straight body position will also help reduce the effects of gravity. The centripetal force towards the inside of the circle is what is keeping her holding on to the bar. To continue going around and around as long as her hands can stand it, she would continue this stretching outward as she goes over the top and bottom and tries to move her legs up past her shoulder angle to keep the center of mass close to the center of rotation. Once she stops adding force, she will stop.