Mouse Trap Car Final Blog!!!!

As Race Day concluded, Paul and I came out victorious. There are a couple things that we had to account for in order to make a winning car. The first thing was Newton's First Law; an object in motion will remain in motion unless acted on by an outside force. Because of this law, we had to make sure we could decrease the presence of outside forces as much as possible. So, when the axle was jamming against the eyelets we used to hold it, we had to remove some of the tape to make sure this stopped happening. This prevented the forward motion of the axle from being hindered; therefore giving us smooth rotations, resulting in more speed. Also, we reduced the amount of friction acting upon the wheels by applying duct tape to the rims (CDs). The next thing we had to wrestle with was Newton’s Second Law; a=fnet/m. Paul and I made sure that we had the most acceleration that we could possibly create. So, we built a frame that has a small mass, using only paint stirrers as our bass. Then to get a large net force we built a lever-arm that is about 18 inches to get the most force that we could achieve. With the net force going up and the mass going down, we were able to get a pretty substantial amount of acceleration. Newton’s Third Law also came into effect, because it says every action has an equal and opposite reaction.  We figured out that the same force that the lever and string applied to the axle was transferred the wheels. The more force the lever creates, the more force applied to the axle, and then the more force on the wheels, creating more speed.

                The two types of friction present were surface friction and wind resistance. So, Paul and I had to make sure that we made the most aerodynamic car possible. to combat the wind resistance we made a slim, streamlined car. A bulky car would create more wind resistance and slow down the car. However, not all friction is bad. Surface friction between the floor and our wheels could actually help when we are trying to propel our car forward. By applying duct tape to the wheels we were able to get more surface friction, so our wheels would gain ground as soon as they began spinning. The only other problem related to friction was making sure that our axle stayed in place, keeping it from creating friction between it and the screw holders. That would decrease the force that was transferred to the wheels. All we did was apply duct tape on the axle to keep it from sliding in order to fix this, and then it was off to the races!

              As far as the wheels go, we decided to use blank disks. We chose these for a number of reasons. First because there mass is distributed evenly throughout, giving them less rotational inertia. Then we applied tape to make sure they were stabilized. One thing about the disks is that they are very light so alone on the axle they were not very stable, but two great minds such as Paul and I were able to fix that. We chose to put four wheels mainly just for stability. We started off with three wheels, but the car leaned to the slide and we realized that this would not be our fastest design. After we put four wheels the car stayed level and achieved greater speed. The wheels were also fairly large because the larger wheels can cover more distance in less time, and since this lab is all about time that was the best idea.

               The conservation of energy applies to our car, because when the lever-arm generates the force on the axle the energy conserved and is transferred to the wheels. The law of conservation of energy states that energy cannot be destroyed, and must be transferred to something no matter what. So we had to make sure that the energy was being transferred in a way that would be beneficial to our car. Applying duct tape to the axle in order to keep it in place, preventing friction from robbing us of some of our energy. In order to get the most velocity, we needed to generate as much kinetic energy as possible. Because since our car had a very low mass it would have to have a large velocity in order to get a lot of kinetic energy.

              Our lever arm was about eighteen inches long. We knew from our study of torque that we could generate more torque with a longer lever arm. Because, torque=force x lever arm, so we left the force the same (the force the mouse trap generated) and we just made a lever arm that was considerably larger than our opponents. This made the torque on the axle greater, causing it to rotate faster, and in turn the wheels spun faster, giving us more speed. We were able to do more work over a period of time, in other words generate more power due to our long lever arm.

         As far as rotational inertia goes we used disks so that our rotational inertia would be less. The mass of the disks is evenly distributed so that results in a lesser rotational inertia. Because they were larger in comparison to the others wheels they were able to cover more distance less time. Due to the greater tangential velocity, which was caused by the fact that the outside of the wheels had to spin faster in order to keep up with the center. The rotational velocity directly relates to how fast the axle is rotating. So, by generating a large amount of torque with our lever arm we were able to generate a lot of rotational velocity.

         We can’t calculate the amount of work the spring does because we do not know how to figure out how much force the spring generated (work = force x distance). Also the spring constantly changes position, and it moves so quickly that we would not be able to calculate the height at which it had potential energy; therefore we could not find the potential energy (mass x height). I believe that we could calculate the kinetic energy if we had a way to measure the speed of the spring. However, we don’t, so we cannot find the kinetic energy either.

         When we made our original design we really did not know what we were doing. As a result, our final design was a very upgraded version of our original design. Originally we were just going to use the mousetrap as the lever arm, but that changed because we needed more torque. Then we had to find ways to secure the wheels better, so that the wheels would not steal energy from the car (I explained how we did this in the first and second paragraphs). Some of the problems were wheel stabilization, generating enough force to get our car moving at blazing speeds, and reducing friction, all of which we were able to fix as I explained already. If I had a redo I would most likely try to find a more rigid lever arm, because ours bent which took some of the energy. If we could find one that didn’t bend I feel like that would have increased our speed exponentially. Also, we could have possibly found a better way than duct tape to stabilize the wheels. However, we came out victorious, so thought these changes would have been nice for more personal satisfaction, they were not needed to thrash the competition.