The two types of friction thataffect the performance of my mousetrap car are rolling friction and staticfriction.A problem that I ran into related tofriction was that the CDs I used for wheels didn’t have enough traction andthey made too much friction with the floor. To solve this problem I cut up fourballoons and taped them to my tires so they would have more traction.
Anotherproblem related to friction was getting my mousetrap car to even start moving.I had to figure out how to overcome the static friction acting on my car. Tosolve this problem, I had to rebuild my car. I lengthened the body added alonger lever arm and more string. This added more force and torque to my car.I chose four wheels for my carbecause I was afraid it would be off-centered and unbalanced if I only usedthree. Plus, I wanted to attach a string on the lever arm in the middle of thetwo front wheels (on the axle).
If I used three wheels (two in the back, one inthe front) the string would have to be attached to one side of the front wheel,not in the middle.I used CDs with balloons wrappedaround the outside of them on each axle. Larger wheels can travel fartherdistances each time they turn. Although, larger wheels take more power andtorque to keep them turning.
Smaller wheels will accelerate quicker than largerwheels but they won’t travel as far each time they turn.Newton’s first law applies to theperformance of my vehicle because since my mousetrap car has inertia it willfollow Newton’s first law. The car will tend to stay at rest when at rest or inmotion when in motion unless acted upon by an unbalanced force (rolling/staticfriction).
We need to try to use the cars inertia to get it to stay in motionlonger so it will go a greater distance. The car won’t move until the stringattached to the axle (outside force) spins the front axel and propels itforward. Newton’ssecond law applies to the performance of my vehicle because in order to get thegreatest acceleration for my car I needed to make sure that my lever arm andstring hooked to the mousetrap and axel created a lot of force to get my cargoing.
I also needed to make sure that the vehicle didn’t have too much mass soI could obtain the greatest acceleration possible with my car. Newton’sthird law states that every action has an equal but opposite reaction. Thisaffects the performance of my car because when the wheels on my car pushbackwards against the floor, it propels the mousetrap car forward. Meanwhilefriction acts in the opposite direction. Newton’s third law elucidates how theforce of the lever arm makes the car move.
Whenyou change the length of the lever arm you change the cars acceleration andtravel distance. I wanted my mousetrap car to go the whole five meters so Iused a longer lever arm so I could use more string to pull away from the frontaxle. This way, energy will be conserved and my vehicle will go farther. One ofthe downsides of this was that using a longer lever arm decreases the pullingforce of my car. Since I use the longer lever arm, my car goes quite a distancebut it doesn’t have the greatest speed. At first I used a shorter lever arm butwhen I would try to start my car the wheels would just spin-out and my carwouldn’t move.
So, I cut a longer lever arm to decrease the pulling force andso I could use a longer pulling string. Using a longer lever arm increases thedistance your car goes and decreases the speed and pulling force. Using ashorter lever arm increases the speed and pulling force but your car may not goas far. Thedistribution of weight of the vehicle must be equal so all of the wheels havethe same traction. An equal distribution of weight lets both axles have thesame amount of traction. If some wheels had more weight on them than othersthen they could resist motion and not turn, causing the car to barely or not atall, move. You need to make sure that none of the wheels are wobbly and thatthey all stay on the ground.
To do this, weight has to be evenly distributedacross all four tires. Your wheels can also slip if they do not have enoughtraction and weight pushing them to the ground. Oneproblem that I encountered in the performance of my vehicle was at my wheelsare crooked and so my car wouldn’t go in a straight line. I solved this problemby re-gluing the wheels on the axle with a piece of cardboard on the back ofthem to keep them level and straight. Another problem that I encountered wasthe string that I was using kept getting caught on the axle and would stopunwinding.
This would stop my car completely and would keep it fromaccelerating to its full potential. To fix this problem I exchanged myyarn-like string for fishing line. Fishing line is very thin, yet strong, so itdoesn’t break or get caught when unwinding.