What are the physics behind a mousetrap racecar?

Answer 1

I don't understand the question. Mousetrap cars are all about physics and the associated engineering.

You start with the energy in a spring and want to convert it, with reasonable efficiency to kinetic energy.

If you use wheels to drive the car, then you have the issues of frictional force and how it limits the rate of energy transfer. If you choose to power the car with a propeller, you have issues of aerodynamics, Newton's law, etc.

Then there the goals: a hill climber? then there is the issue of torque; distance? then efficiency is critical (rolling friction, etc.); max speed? then weight and rotating mass become critical (minimizing moment of inertia); etc.

Then there are the issues of the transmission of power - just how do you drive something from the mousetrap? Some people have the bar pull on a string wrapped around an axle. But you can also use something like a gear.

The spring is powerful when it starts to let go, but its force decreases as it returns to its "snapped" position. How do you deal with this unevenness? Do you put on a big flywheel to capture the initial torque?

Etc.