Mouse Trap Car


Project Review:

          The challenge our group was given was to build a racecar that is only powered by a mousetrap. We were able to strive for distance or speed. Our group chose distance. Our first design for our car consisted of mainly legos; small lego tires in the front, big lego tires in the back, a large gear spinning a smaller gear, which spun the rear axle and wheels really fast. The chassis also consisted of legos. For the mousetrap we extended the lever arm by attaching a cut, metal coat hanger. We attached the mousetrap to the car by using duck tape. For the pull cord we used fishing line. Our first design didn’t work and the car didn’t move and inch so we decided to change it a bit. We decided to shorten the car, replace the fishing line with cotton string and take off the gears. (The gears needed too much force to make the car move but once we removed them the car went really far.)

          Some areas of physics my group incorporated into our car are friction, spring force, wheel-axel ratio, rotational inertia, and a lever arm. The specific topic I have chosen is the lever arm. We included a lever arm into our mousetrap car and extended it by quite a bit to extend the cars distance. The longer the lever arm the wider range of motion the car has. The shorter the lever arm the more speed the mousetrap car is. We realizes that if the lever arm is too long it wouldn’t have enough force to pull the string which makes the wheels turn. We shortened it a bit and once we got the right ratio, the car went beautifully.

Time Trial Results:


Time over 1 meter

Speed over 1 meter

Time over 3 meters

Speed over 3 meters

Distance the lever arm pulls it

Overall Distance


3.34 s

0.2994 m/s

5.41 s

0.5545 m/s

2.85 meters

4.3 meters


3.12 s

0.3205 m/s

6.08 s

0.4934 m/s

3.94 meters

5.52 meters


3.37 s

0.2967 m/s

7.83 s

0.3831 m/s

4.64 meters

4.91 meters


            During the time trials, our mousetrap car went faster over 3 meters instead of 1 meter because the car was accelerating. The cars acceleration is the lowest right before the mousetrap goes off because the car is not moving. The acceleration of the car would be the highest right around the time where the lever arm is at the top of the arc. The car stops accelerating when the lever arm hits the chassis. If we wanted our car to coast for a greater distance, we could lighten the car by taking off all the heavy tires and replacing them with something light. We could also take off more legos from the chassis.


Race Day Results:

            Mass: 208 grams

            Distance: 6.7 meters

            Overall place in drag race: 2nd

            Efficiency rating: 31.0447612


          What worked well on our car was that the legos were easy to take apart and put back together and that they held together even when dropped. I think the biggest thing our group could do to improve our car’s performance is by taking off weight and maybe even using a stronger mousetrap. What I enjoyed the most about this project is that we were able to design our own car and didn’t just build it from a kit. I’m also glad that everyone did his or her job in making the car and nobody truly slacked off. One Challenge that my group mainly faced was trying to get our car to move. We first had to find the right ratio between the lever arm and length of car. We then had to focus on finding a new string. The fishing line we chose at first kept breaking off. We then switched that string for wire, which we couldn’t even wrap around the axel. We were finally able to get a hold on some cotton string which made the car run really well.





8 Responses so far »

  1. 1

    juni said,

    hi your my idol you rock i am make a mouse trap to im in the 8th grade is it easy

  2. 2

    anthony said,

    well, yes sort of

  3. 3

    Dinkleburg said,

    I love potatoes

    love Dinkleburg

  4. 4

    Dinkleburg said,

    mmmmmmmmmmmmmmmmmmmmmmmmmmmm….. potattp
    aka potatoes

  5. 5

    pattdapteraggadon nwo avliabel at teh sttroe

  6. 6

    Hello, this weekend is nice in favor of me, because this point in time i am reading this great educational post here at my house.

  7. 7

    catxerina said,

    how far did your car travel

  8. 8

    John said,


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