If you know anyone who teaches physics at the high school or college level in the Washington DC area, please pass this along…
I have worked up a great demonstration using bicycle wheels. It goes through the calculation of the total kinetic energy of a bicycle by calculating separately the translational kinetic energy of the bike and rider and the rotational energy of the wheel. Using hubs and rims that were donated by Velocity USA and spokes that were donated by Sapim, I have built two wheels that are identical in total mass but differ greatly in the location of the mass. One wheel has a lot of its mass in the center, and the other has a lot of its mass at the perimeter. These wheels are mounted onto Park bike stands next to each other in front of a class. By using simultaneously falling weights, it is easy to see that the wheels accelerate at different rates, attain different “speeds”, and then slow down at different rates even though both have the same total kinetic energy. I go through a detailed explanation of the calculation of moment of inertia and angular velocity, either with or without calculus, depending on the class.
My goal is to inspire young people to study science and engineering. I’m happy to “take the show on the road” at reasonable driving distances.
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