MouseTrap Car Report

This past week our physics class did something really exciting! We got to build mousetrap cars! It was a lot of fun and I can't wait to share the experience with you guys. This post will include the following...

1.) Speed of the car and the place it came in 

2.) A picture of the car

3.) A picture of the car with labels 

4.) A video of my race 

5.) The Physics behind the MouseTrap car

6.) Personal Reflection

Part one: Speed of the car and the place it came in 

Speed: 3.03s per 5 meters

Place it came in: 2nd

Part two: A picture of the car

Part three: A picture of the car with labels 

Part four: A video of my race 

 

Part five: The Physics Behind the Mousetrap Car 

a.) Explain how Newton's First, Second and Third Law applies to the performance of a car.

Newton's First Law: The law states that " an object at rest of in motion will remain at rest or in motion unless acted upon by an external force." In the case of cars, the external force would be the engine. If the engine fails to act on the car then the car will remain at rest or in motion. 

Newton's Second Law: The law states that " force is directly proportional to acceleration, while mass is inversely proportional to acceleration." In a car, the more force you apply to the pedal, the more force is applied on the engine. The more force that is applied on the engine, the more your car accelerates. However, also with cars, the greater the mass, smaller the acceleration will be. This is because a larger force will be needed to act upon the greater mass. 

Newton's Third Law: The law states that " for every action there is an equal and opposite reaction." In cars this applies to the wheels interaction with the ground. The ground apply only as much force on the tires as the tires apply to the ground. Therefore, the more force we apply to the ground, the greater  the force back will be. If the ground didn't have an equal and opposite reaction , then the wheels would just spin in place and we would go nowhere. 

b.) What part of your car relied on friction? How did you utilize it? Which part was a disadvantage by friction? 

The part of my car that relied on friction was the axle and the wheels. I utilized the friction on my wheels, by adding friction tape around the edges of my back wheels. This allowed for the wheels to have a better grip on the floor and not loose any acceleration by spinning in place. I also utilized it on where the string wrapped around the axel. I used the spool to create more friction causing the axel to spin more and in turn spinning the wheels more. The part that was a disadvantage was the friction where the axel met the frame. The more friction there is at that point, the slower the axel may turn which will cause the wheels to not spin as much as they might with less friction. 

c.) How did the size of the wheels affect your car's performance? Make sure to discuss this in terms of torque, force, and lever arm. 

In a mousetrap car, the greater the size of the wheel is, the greater the amount of required torque will be to start the car and keep in turning. Torque equals force multiplied by lever arm. The greater the lever arm is, the smaller the amount of force needed will be. In other words, if I have a long lever arm, I will only need a small force of like the the one applied by a a mousetrap, to create the same amount of torque I need for my wheels to spin. 

d.) Discuss the conservation of energy in how it relates to your car. Be sure to include information about your car's use of potential and kinetic energy. 

The law of the conservation of energy states that " the total amount of energy in a system remains constant. Although energy within the system can be changed from one form to another or transferred from one object to another. Energy cannot be created or destroyed, but it can be transformed." In relation to my car, the energy within the system cannot be created or destroyed, but it can be lost to forms of energy such as heat and sound. In my car, the wheels and the ground, the axel and the frame, and the string against the axel all have a little bit of friction. This means that some of the energy is being transformed into heat and sound because of it. Now let's discuss potential and kinetic energy. The potential energy of my car is stored in the loaded mousetrap. When the trap is released, all of that potential energy is converted in kinetic energy. Due to the law of the conservation of energy,  the energy I have at the beginning will continue onward, so none is lost in this conversion. The energy is just transformed. 

e.) What role did rotational inertia, rotational velocity, and tangential velocity play in your functioning car? 

To begin,  rotational inertia is the resistance an object has to changing its state of rotation. In other words, the greater the distance between my wheels edges and the axis of rotation, the greater  rotational inertia. Now rotational velocity controls the number of rotations of the wheels of the car. Finally, the tangential velocity of the wheels are how fast your car is going. 

f.) Why can't we calculate the amount of work the spring does on the car? Why can't we calculate the amount of potential energy that was stored in the spring and the amount of kinetic energy the car used? Why can't we calculate the force the spring exerted on the car to accelerate it?

We can't calculate the amount of work the spring does on the car because the force and distance are perpendicular. We can't calculate the amount of potential energy that was stored in the spring and the amount of kinetic energy the car used because we don't know the amount of work that was done on the car. We can't calculate the force the spring exerted on the car to accelerate it because the force and distance were perpendicular.

Part six: Reflection 

a.) My final design was only slightly different. The only change was that I added a spool on the back rod. What prompted the change was that my car was going far past the required 5 meters, but very slowly. By adding the spool, I increased by velocity, but I lost some unneeded distance.

b.) The only grand problem I had was that my car wasn't fast enough. It was going pasty the required distance, but very slowly. To solve this I added a wooden spool on the back axel. By adding the spool, I increased the velocity and lost some unnecessary distance.

c.) If I were to do this project again, I would add lubricant to where the axel meets the frame to lower the friction.

d.) The only thing I would do differently is set reminders for due dates. Otherwise, I am very happy with how everything turned out. I did my research early on. I made my designs and got my materials before the due dates. I started building the day after and continued to work on it each day outside of the allotted class time.