Activities for the Wireless Dynamics Sensor System - Vernier ...

Activities for the Wireless Dynamics Sensor SystemTEACHER INFORMATIONWDSS Bungee Jumper1. A bungee jump provides an excellent opportunity to let students see a link betweenforce and acceleration, assuming that they first have an understanding of what eachmeans.2. Here are a number of web sites with information on the technology of bungeejumping, its history, some fantastic images and the physics involved.• Reporter’s Notebook: South Pacific Ritual Bungee Jumping – This is a newsreport on the land diving ritual, the Naghol, performed on Pentecost Island, one ofmany making up Vanuatu.http://news.nationalgeographic.com/news/2002/11/1125_021126_TVVanuatu.html• Steve Fettke Bungee Jumping – This site contains lots of bungee facts, detailsabout the equipment used, photographs, and videos.http://www.fettke.com/bungee/equip.htm• The Oxford Stunt Factory – This organization performed the bungee jump shownin the Bond movie Golden Eye. Images of this and other stunts are available here.http://www.oxfordstuntfactory.com/html/stunts.htm• Vertige Aventures – This company manufactures bungee ropes and providesinformation on their construction.http://www.bungee-jump.com/xvms.htm3. The bungee cord needs to be selected for reasonable elasticity. The rubber cord usedin a paddle-ball toy works well for this experiment. You can also create a cord byconnecting several smaller rubber bands together.4. When discussing the accelerometer reading, it is proper to refer to it as a measure ofNormal Force per Unit Mass, with units of N/kg, where “normal” is in the directionof that particular accelerometer. This is what the accelerometer is actually measuring.(Note that it is not the net force per unit mass which would be acceleration.) Amotionless accelerometer oriented in the vertical direction will give a reading of+9.8 N/kg when pointed up and –9.8 N/kg when pointed down. A motionlessaccelerometer oriented in the horizontal direction will read 0 N/kg. An accelerometerin freefall will give a value of 0 N/kg regardless of its orientation. Since most peopleprefer the measurement be in m/s 2 , we have used these units in this manual.6 © 2007 - Vernier Software & Technology