Design a Mousetetrap Car With Tinkercad

mousetrap cars are mostly compettition subjects for high-school physics classes, and basically you need to build a small car powered by a single mousetrap and do stuff with it. sometimes it must be the fastest, the longest, or have a return system inside it. today i'm going to teach you how you build these things using tinkercad.

a huge thanks to youtuber mr. rober for most of the info in this project.

just your computer, a notebook, and a pencil

so the basic idea of a mousetrap car: a wooden cart with a wheel tied to a string leads to a winded mousetrap, which pull the string back, rotates the wheel and so on.

to understand the science inside the car, we first need to know the super-not complicated word; mechanical advantage(we'll call it MA for short). for an example, imagine you're a caveman architect and you're given the order to build a table-style stone grave. to do this, we need to push up a flat stone up to a another stone. to do this, we can either pull up the stone directly or make a ramp and push the stone up. the first one will take a short amount of time, but it will feel heavy. the second one will take a little more, but it would be lighter. thus, the MA is 2. still to hard? just think a screw is a nail with a ramp around it, it will take more time than a nail to stick in up a wall, but it would be a lot more easier. more mechanical advantages are around us in various tools or building methods. the mousetrap cars will be on reverse when it comes to MA. MA actually dosen't cares even if you spin it forwards or backwards. but we'll need to spell the MA on reverse, too. so instead of 2, we'll spell it 1/2.

in every case, we'll need to start off with a single mousetrap. for starters, i made a simple rubber-band powered switchless mousetrap that you can use on your car. and if you're doing a team race, don't improve the mousetrap. that's cheating. the normal looking one is for modeling, and the disassembled one is for printing.

now for the real part. to design a long-range car, we need to get the smallest MA, so we can really save up the energy. which means a reeeeeeeally slow but energy-saving car. to do that, we'll need to build a long lever arm, so it gives out the smallest MA as possible. but if you make it too long, gravity slows you down, so make it lightweight as possible. the wheel axle and the wheel-gound friction matters too, so make the wheels like a CD, and increase the axle hole's diameter(installing a ball bearings works better, but we're using tinkercad only). sometimes people turn their back wheels into one giant big wheel, which cranked down the MA seriously. but then, it takes energy to have that giant thing rotating(called rotational inertia. we'll call it RI for short). wheels are kinda like a temporary storage for energy. giving it a big wheel saves up more energy, but it loses some because of the RI. it's better to have normal-sized wheels and lose no energy at all. and big wheels are often hard to steer. so try to decrease the amount of RI used on your wheel. the world-record holding car uses a pully system at the middle, so it gives out a MA of 1/4608.

i left an example car you can print out.

for the fastest car, we now need the biggest MA, because now we're measuring the speed, not range. so we basically need a short lever arm, so we can dump all the energy in one short burst. this is kinda like a dragster car, which is a bunch of SCREEECH ZOOM(just kidding)which is a kind of a racing car that starts off with a really high speed(0~100km in 0.8 seconds). thus some of them actually tries to take off(so they actually have super small extra wheels at the back). what's really iconic about them is they have really big back wheels and small front wheels, to reduce weight and friction. i suggest your follow that idea. and if you're going to make it lightweight, give your wheel some grip, because if you slip, that's both wasted energy and dangerous to your car.

this too i left an example.

our lesson is finally done! now you know how to beat every mousetrap car championship with your own car! again, a huge thanks to mr. rober for all my knowledge in this project. be sure to like and i'll see you guys at my next project.