The Presentation (powerpoint):MecE 200 Technical Presentation
Date: November 9th, 2005
Time: 9:30 am
Place: MecE 4-1
Speaker: Michael Rory Dawson (1097767)
Department of Mechanical Engineering
University of Alberta
The Mechanics and Nomenclature of Footbag
Abstract
In this talk I will be describing “footbag” from a technical perspective. A Hippy and a Fitness trainer invented Footbag in 1976. Since then it has developed internationally as both a hobby and competitive sport. This presentation will focus on the physics and technical nomenclature of “freestyle” footbag.
Previously the way tricks were described was undefined and this caused a great deal of confusion especially when trying to communicate over the internet. In this presentation we will use physics and technical nomenclature to derive a “coordinate system” to conclusively define and describe every possible trick. In addition, this coordinate system will also include a way to gauge difficulty making it very useful for competition.
http://www.shredmonton.com/media/The%20 ... ootbag.ppt
The Notes:
Slide 1:
- introduce yourself
- ask what is footbag?
Slide 2 (underwater pic):
- This is footbag (look very serious)
- *pause for effect*
- Just kidding!
Slide 3
- You might know footbag as "hacky sack", but this is a misnomer blah blah...
- Pull out 32-panel, mr. sandbag, and hacky sack (I actually had the same one in the picture).
- Describe the qualities of an ideal footbag -> stallability, weight balance, high coefficient of friction, ect
- the hacky-sack is obviously the inferior bag.
- explain the difference in impulse/momentum (ft=mv) between kicking and stalling DEMONSTRATE!
- kicking is contacting the bag with your foot moving up
- stalling is contacting the bag with your foot moving down
Slide 4
- Footbag freestyle is all about tricks and linking them together
- What is a trick?
- Read "The lumberjack" ... "blah blah blah! This is ridiculous!"
- Footbag needed a "coordinate system" and a "free body diagram" to describe the tricks properly and concisely (frame of reference)
Slide 5
- definition of a trick
- ADD components
Slide 6 (blur picture)
- "And here's me doing all the components at the same time..."
Slide 8 (jobs)
- DEMONSTRATE
- put footbag on toe then set it and dance around like in blur picture then catch on opposite toe.
- walk through the notation
Slide 9 (dexterities)
- one of the main trick components are "dexterities"
- draw imaginary z axis perpendicular to the ground
- put your knee at the origin and rotate around the z-axis
- your leg will sweep out the volume of a cone
- can rotate clockwise/counterclockwise
- explain diff between in out and out in
- picture bag as sphere inside the volume of the cone
- for a trick to be "clean" the bag must be completely inside the cone
- DEMONSTRATE atw
slide 10(picture from footbag brasil)
- reinforce cone example
- make joke about it being in portuguese (fora - out and dentro is in)
slide 11 (uptime/downtime)
- as engineers we want to make things more efficient
- easiest time to picture dexing bag is when vertical component of velocity is zero
- why not dex on the way up and way down!?
- DEMO magellan
slide 13 (shred30)
- summarize all previous concepts
- adds/jobs play a role in equation
- walk through equation
- talk about strategies to improve score
- SHOW SHRED30 VIDEO (I used mine from shredmonton 05)
slide 14 (shred30)
- walk through how to calculate my awesome score
- The end!
Questions?! Feedback?
