Carmen+Moore

Double Twist Basket Toss **Background Information**  A cheerleading stunt group consist of two bases, a back and flyer. The two bases stand to the left and right of the flyer and the back stands in the back of the flyer. The flyer is of course the one top of the group as shown in the picture to the left. When setting up for basket toss the bases must grab eachother's wrist in weaving basket fashion, hence the name of stunt being called a basket toss. Can you picture it? No? Well this is what it looks like! The flyer places her feet on the hands of her bases and the back wraps his/her hands around the flyers ankles, like this.

**Explanation** **Circular Motion/Conservation of Angular Momentum**   Circular motion is the cross product of force and radius. When twisting out of a dismount the flyer needs to be able to make a full rotation and be able to stop their rotation. They increase their ability of rotating fully around by pulling their arms in and crossing them over their chest. They bring their rotation to a stop by opening their arms to slow down their rotation. ** Angular Momentum **  Angular Momentum determines how fast the flyer will go in the spin. The flyer can generate angular momentum by pushing off of her bases feet as well as increasing vertical velocity. While the flyer is pushing down on her bases hands, the bases are creating a counter force by pushing the flyer's feet upward. ** Velocity**  A larger mass position will decrease the flyers velocity in the air, this will happen if the flyer keeps her hands open, this concept is referred to as conservation of angular momentum. A smaller mass increases the flyers velocity in the air, this will happen if the flyer keeps are arms tucked close to her body while she is spinning. Velocity is a vector quantity which refers to the rate at which an object changes its position. When the cheerleader is twisting she must increase her velocity in order to complete a full rotation. **Impulse **  The landing of the cheerleader is cushioned by the support of her bases, which catches the cheerleaders in a cradle position. They do this by bending their knees during the catch, which allows them to more easily absorb the force of landing. This in turn reduces the forces acting on the cheerleaders during landing. Impulse is decreased by decreasing the time before impact. As the flyer opens up her arms she slows down thus decreasing the time before impact. The bases absorb the force of the flyer by catching her thus making the force smaller, this concept is explained by the impulse equation, I=fT.

<span style="font-family: 'Comic Sans MS',cursive; font-size: 110%;">**Slow Motion Video** <iframe id="dit-video-embed" width="640" height="360" src="http://static.discoverymedia.com/videos/components/dsc/340ea3635e7eb5e53d51c76efecc569aaa93cf57/snag-it-player.html?auto=no" frameborder="0" scrolling="no" allowtransparency="true">

**Categories**  Velocity, Conservation of Angular Momentum, and Circular Motion(Torque), and Impulse <span style="font-family: 'Comic Sans MS',cursive; font-size: 140%;">**References** Discovery Channel. “Time Warp: Cheerleaders in Slow Motion.” //Discover Channel//. Web. 20 Dec. 2011. <http://dsc.discovery.com/‌videos/‌time-warp-cheerleaders-in-slow-mtion.html>.

Mr.Fizzix. //The Physics of Cheerleading//. N.p., n.d. Web. 20 Dec. 2011. <http://thephysicsofcheerleading.homestead.com/‌index.html>.

NBC. “Figuring Out Figure Skating.” NBC. //NBC Learn//. Web. 20 Dec. 2011. <http://nbclearn.com/‌olympics/‌cuecard/‌47296>.

Real World Physics Problems. “Physics of Cheerleading.” //Real-World-Physics-Problems//. N.p., n.d. Web. 20 Dec. 2011. <\http://www.real-world-physics-problems.com/‌physics-of-cheerleading.html>.