Mouse Trap Car

Mousetrap car. Yes, I said mousetrap car. If you think this sounds ridiculous, I admit, I had the same initial reaction. 

I was assigned to make a mousetrap car for physics after studying how simple machines work. 

So, here's how it turned out.... 

My first question was, "how am I going to make this work in the first place?" 

After studying the components of a mousetrap, here's what I came up with. I realized that the trap is a 2nd and 3rd class lever. 

In my previous blogpost, I discussed levers, how they work, and what types there are. 

Recall:    2nd class lever =  The effort force is at the end while the load is situated in the middle. 

               3rd Class lever = the load is at the end, the fulcrum in the middle, and the                                             effort force is in between. 

When a Mousetrap car is set it works as a 2nd class lever. 

In this case…. 

Load = Arm of the spring that is being pushed down to compress the spring. 

Effort force = Your fingers on the end of the snapper arm 

Fulcrum = Pivot point in the middle of the trap 

When a mouse trap is released it works as a 3rd class lever 

Load = The snapper arm 

Effort Force = Spring arm 

Now I knew that the lever was going to power the car.  I needed wheels to make it move, but how would I connect wheels to the lever arm.  I know how the wheel and axle work, so this is the type of model I came up as the final product of the car; 

And a video 

(In the above video, the car goes 15 feet) 

Here is why I chose to build it this way:

Notice my savvy design skills

The car is not very flashy because my goal was to go maximum distance over a short period of time. To do this, the friction and weight of the car must be as small as possible. 

I choose discs as my wheels because they were thin. In this particular project, when the wheel is thin, it minimizes rolling resistance with the floor. There is also a fabric around the disc to ensure that it does not slip while accelerating. 

The frontal area of the car, unlike the back has small wheels to minimize air resistance.  

Wow Helena that was awesome!!!! 

Yes, I know 

How did it work??? 

When a  mousetrap is set, it is full of potential energy that converts into kinetic energy when released. The design of my car allowed the potential energy to be transferred to the axle.  

When the trap snapped closed and yanked the string, the friction between the string and the axle caused the axels to rotate and thus spin the wheels making the car more forward. 

I also decided not to make my lever to arm too long. Yes it would have made it go farther, but it was also required to go fast. 

The car may not be perfect, but at least I didn't do this!