Three variables or foundations limit the speed of a Pinewood Derby® car. Addressing each area results in faster cars!
Potential Energy - Pinewood Derby® cars are gravity powered. Their potential energy is the amount of energy available to be converted into motion or kinetic energy. Maximize potential energy by tweaking the amount and, most importantly, the location of the weight in the car. Learn how to address this foundation in the Weighting article.
Friction - Friction limits the use of available potential energy. Energy is lost from surfaces rubbing against each other. The wheels, axles, car body, track, and air are all sources of friction. Reducing friction is key to increasing speed and is addressed in detail in the Wheels, Axles, Aerodynamics, Alignment, Body, and Lubrication articles.
Rotational inertia - It takes a certain amount of energy to start a Pinewood Derby® car rolling down the track. Heavier objects need more energy than lighter objects. Reducing the car’s rotational inertia leads to quicker starts and faster times. Reducing rotational inertia is discussed in detail in the Wheels chapter.
Articles in this series (click to read):