Victor and Craig's mousetrap race car

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Mousetrap car competition is a fun and educational activity in which students can learn to build a mousetrap car. Students can learn how a mousetrap car works and the physics concept behind it.
 
A mousetrap-powered car is a vehicle that uses a mousetrap for a motor. These cars commonly have a string attached to the mousetrap and axle. When the mousetrap is released the string will pull the axle which will cause the car to be mobile.

Victor Rosas

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Website creator and assistance in building the mousetrap car.
 
 
 

Craig Kalpakain

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Mousetrap car builder and assistence in website creation

Physics is involved in just about everything mankind does. It’s almost impossible not to confront physics in our daily lives. Building these mousetrap cars gave us a perfect example on how physics concepts can relate to anything. These mousetrap cars shows us the force the mousetrap must have. Newton’s laws are also a great example on how physics concepts are involved in making these mousetrap cars. The mousetrap car helps us realize the potential, and kinetic energy it has. They can help us discover either the centripetal motion of the wheels or help find missing variables by using kinematics.

 

Physics concepts relate to mousetrap cars because we can discover the force the mousetrap must have in order for the cars to move. Using equations like F = MA, we can discover how many newtons (N) the mousetrap needs in order for the car to be moving at that rate. Another factor that is involved in building these mousetrap cars is the mass vs. acceleration. Using the equation F = MA, you can see that the smaller the mass is, the faster the acceleration is. This same concept works in reverse. The faster the acceleration is, the less mass it is. Also physics concepts relates to mousetrap cars because in physics we learned that, in order for the mousetrap cars to move, it must have force acting upon it (ground) which pushes the car up. So both the force of the ground and the force of the mousetrap car must be equal in order for the vehicle to work go forward.

Physics concepts relate to mousetrap cars because Newton’s laws are involved in these mousetrap cars. Newton’s first law states that, “everybody continues in its state of rest or uniform motion in a straight line unless it is compelled to change that state by forces impressed on it.” The mousetrap car relates to this because the mousetrap car does not move until the force of the mousetrap moves it. The mousetrap car will eventually be compelled to change by the forces impressed on it. Newton’s 2nd law states that, “the acceleration is directly proportional to the force and inversely proportional to mass.” This relates to the mousetrap car because it says that the object will only move if there is an unbalanced force. Both speed and direction can be changed due to the unbalanced force the mousetrap car has. The force of the mousetrap is greater then the force the air resistance or pressure in front of the car. Newton’s 3rd law states that, "for every action, there is an equal and opposite reaction." Newton’s 3rd law relates to mousetrap cars because when the mousetrap car propels forwards, the size of the force of air is equal to the size of the force of the mousetrap car. But the direction of the force is backward because the mousetrap car is moving forward while the air is being pushed back.

Physics concepts relate to mousetrap cars because mousetrap cars are a perfect example of potential and kinetic energy. Everything has potential energy because everything is in a stored state until it is releaseed. When potential energy is released,  the energy of motion or the energy a moving object has now converted into kinetic energy. A mousetrap has potential energy stored in the springs. Once the springs are released of pressure, the mousetrap now has kinetic energy. The kinetic energy is what moves the mousetrap car in motion. Now the law of conservation of energy stresses that, “energy cannot be created or destroyed; it may be transformed from one form into another, but the total amount of energy never changes.” This means that the potential and kinetic energy is never just appears or disappears. An example of this would be an ice cube. The ice cube is not created. The ice cube always existed. It is just in a different state. Instead of being a liquid it is now a solid hence the term law of conservation of energy. Much like the ice cube the potential energy always existed in an object. The potential energy is transferred in kinetic energy and then eventually transferred back to potential energy. Friction converts energy into heat and sound, which removes energy from your motion. The mousetrap car in motion can acutally create heat around it because all the energy expelled from it is converted into the heat you feel and the sound you hear. So the potentail and kinetic energy is just transformed into a new state.The vehicle rolls to a stop because friction removes the energy. Without friction a mousetrap car could roll on forever. But it is also important to realize how friction could be a good and bad thing. As I just said, friction can be a good thing because the mousetrap car is suppose to reach a reasonable and/or logical distance in our world. But the friction could also be bad because it can hinder a mousetrap car’s ability to move or move fast. The more friction the car has on the ground, the more force needed in order to make the car move forward fast. So the more friction between the wheels and the ground the slower the mousetrap car will go.  Friction is bad if you wish for something to move at a fast rate. But sometimes fiction is needed in order for the car to propel forward. If there were no friction,  the mousetrap car would have difficulty moving  in one direction. The mousetrap car may be slipping all over the place because it has no grip on the ground. So friction can either be good or bad.  

Physics concepts also relate to mousetrap cars because we can discover either the centripetal motion of the wheels or help find missing variables by using kinematics. Centripetal motion can be very useful in designing anything that deals with something that spins. The wheel’s centripetal motion on the mousetrap car is a perfect example of a concept in physics. One can discover the period or frequency the wheel has. Knowing this can help you know the speed the car is going at and know the centripetal force it has. Equations like a = v(squared) / r, F = m (v(squared) / r), and V = 2(pie)r / t can all help one configure and design a vehicle which is capable of making certain requirements (like 5 meters). Centripetal motion also goes hand and hand in solving equations using kinematics. For example finding the average velocity is the same for finding the circumference of a circle. Kinematics is the science on how objects move. Physics relates to mousetrap cars because one can calculate, speed, mass, time, distance, and acceleration of the mousetrap car. For example, if I only knew the distance and time the mousetrap car took. I could find the velocity of the vehicle by using the equation, d = ½ (Vf + Vi) t. All equations like, Vf = Vi + at, d = Vit + 1/2at(squared), Vf(squared) = Vi(squared) + 2ad, Vavg. = (Vf + Vi) / 2, F = ma, w = mg, v = d / t, and a = v / t can all be used to help analysis the mousetrap car (analysis the kinematics) as much as possible.

As you can see, a mousetrap car is a perfect example of physics at work. One can learn the force a mousetrap car has. One can visualizes all three of Newton’s laws, and realize how those laws apply to the mousetrap car. One can realize the potential and kinetic energy in a mousetrap. One can also discover either the centripetal motion of the wheels or help find missing variables by using kinematics. A mousetrap car is not only related to physics concepts, a mousetrap car is physics at its best.

          The competition was to build a vehicle powered solely by the energy of one standard sized mousetrap. The vehicle must reach 5 meters in the shortest amount of time, in order to win the competition. The mousetrap could not have any potential or kinetic energy other than what can be stored in the trap itself. The vehicle had to be self started, and was not allowed to receive a push forward. The vehicle had to steer itself. The vehicle could not contain any electrical equipment that could have been operated by any persons before the vehicle is moving and once the vehicle is in motion. The time started once any part of the vehicle passes the start line. The time ended when the point of the vehicle that started the timing passes over the 5-meter mark. The races were done at a smooth level floor outside our classroom.

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          While building this mousetrap car, we were confronted with many problems. First it was difficult to find wheels that would work best for our car. We overcame this problem when we decided to go the Hobby Shop and look around till we found what we wanted. Our next problem was what we should use as an arm. At first we used a fishing pole but then we decided that the arm should be a stronger and thinner material. So we decided to use a fiberglass rod. After we finished building the mousetrap car we were faced with another problem. The mousetrap car barely moved. We discovered that the reason the mousetrap car didn’t move was because of the string we use. The string would get tangle and would get stuck. So we decided to use a newer string with less hair around the edges. We also discovered that the string would be pulled faster if we rolled the string up from side to side on  the axle. We knew that this was better than rolling the string up in random layers back and foward.