Braking Distance Lesson 
Content Area: Physics (1112) Topic: Kinematics SubTopic: Braking Distance Computer requirements: Vensim, STELLA^{TM} or Excel Essential Questions or Ideas to address:
The lesson (90min block): Students use various resources to determine the braking abilities of one or models of cars. The data given in car magazines is usually presented at distance to stop from 60 mph. From this information and using the appropriate conversions, students calculate the braking accleration in ft/sec^{2}. They also create a table of velocities, converting 20, 30, 40, 50 and 60 mph to ft/s. Then students build or use a model to look at the stopping distances for these other velocities. A graph of stopping distance vs. initial velocity is developed and students are asked to determine if the relationship is linear. If students have been assigned different vehicles with different braking accelerations to model, then students can also compare results between vehicles. An applet may be found at: http://www.mta.ca/faculty/science/physics/suren/Brake/Brake.html Common misconceptions addressed:
Evaluation of lesson effectiveness:
Students generally enjoy using car magazines to get data on
vehicles. They struggle with the unit conversions. Use of
the model is fairly simple and the graph produced is fairly clear to
read and appears in math and physics textbooks. There is value in
relating the physics equations they are learning to real world
applications. Math topics: Linear and quadratic equations,
graph interpretation for those equations, using a graph to determine a
relationship, conversion of units Standards: MSDE (from the website as of 9/05):
The standards do not directly address kinematics, but an understanding of motion is necessary before students can address the standards as they appear here. National Science Standards:
AAAS Benchmarks:

