The concept most central to us building our mousetrap cars is energy. Energy is defined as having the ability to do work. Work is motion that result in something being done. Energy can be classified in a number of ways. Most commonly energy is classified as potential and kinetic.
Energy cannot be created or destroyed it may be transformed from one form into another, but the total amount of energy never changes.
By winding the spring on my mousetrap car, I am storing energy in the spring as potential energy. This stored potential energy will turn into kinetic energy as the mouse-trap car begins to move. Friction converts energy into heat and sound which removes energy from the motion of the car, causing the vehicle to roll to a stop as its energy is removed. So the car that loses energy the quickest will go the least distance.
When designing a mousetrap powered car, there are two variables that truly determine the overall performance these are friction and energy. Friction is what slows and stops the car, energy is what moves it. If my car encounters too much friction, the energy supply will be consumed too quickly and my vehicle will not travel very far or accelerate very fast!
By evaluating every moving component on my vehicle and decreasing the amount of friction at each point, my car will improve. My goal when building a mouse-trap powered vehicle is to reduce friction to the lowest possible force. The smaller the frictional force, a larger amount of energy will be available to propel my car.