Mouse Trap Car

How Newton's first, second, and third laws apply to the performance of the car

              First Law: An object in motion will stay in motion, and object at rest will stay at rest unless acted upon by an outside force. In other words, the mouse trap car will not move unless an outside force will cause it to move (the string attached to the axis). It will keep moving unless an outside force acts upon it (Friction, or in our case, a wall)

              Second Law: A=F/M. To obtain a greater acceleration, you need to trim down the mass of the car as well as apply more force to the car, which usually means wind up the rope nice and tight.

            Third Law: Every action has an equal and opposite reaction. When the mouse trap wheels push backward against the ground the ground propels the car forward.


What are the two types of friction present? What Problems related to friction did you encounter and how did you solve them? How did you use friction to your advantage?
                 
                     The two types of friction is the friction created between the wheels and the floor to get it moving in the first place, which is known as static friction, and then there is kinetic friction or the resistance against a moving object. Friction took part in two key places. Firstly, the friction between the wheels and the ground provided stabilization, yet at the cost of speed. The other force of friction took place between the wheels and the axel. The more frictionless the wheels of the car were, the easier it was to spin and travel faster.
 At first, we had to overcome static friction to make our car move in the first place, we did so by adding more string and widening the axel to create more force to overcome the frictional barrier. However, we created traction between the floor and the tire by adding tape to help stabilize the car.

What factors did you take into account to decide the number of wheels? What kind of wheels did you use in each axle?

Stabilization was a key factor in choosing to have four wheels. Also, we felt that the wheels would complement the body of the car better than one wheel. Furthermore, We wanted our wheels to be generally larger in the back so we would have a greater tangential velocity or cover more ground per rotation. Therefore we chose CDS for the back. Another reason for using CDs is that they lack mass which causes a greater acceleration, Newtons Second Law. Finally, since the axel of the CD were much smaller than the outside, if the CDs had the same RPM the outside wheels would have to travel a lot faster to keep up with the axel.

Discuss the conservation of energy in how it relates to your car.

Since energy cannot be created nor destroyed, the more potential energy you have built up the farther you car will go because it has more energy. For example, you want a taut string compared to a loose string because their is more potential energy built up within the string and therefore has more force to convert into kinetic energy. Since Kinetic energy equals the change in work, the more kinetic energy you have the more work has been done.

What role did rotational inertia, rotational velocity, and tangential velocity play in your mousetrap car?
 Rotational Inertia, particularly affects your starting acceleration. Therefore to decrease your rotational inertia, you want wheels with a smaller mass and more traction.

Rotational velocity is the amount of rotations per second. Rotational velocity actually was a problem with our mousetrap since the front wheels were moving having to rotate faster to keep up with our back wheels which had a greater tangential speed. Because of this, it caused our mouse trap to taper, twist, and turn so that it did not make it to the finish line.

Tangential velocity is the distance traveled over time. It is important to have a high tangential velocity so you can go faster. To achieve a higher tangential velocity, you must have larger wheels that can travel a greater distance per rotation.

The reason you cannot calculate work is because the force is not parallel to the distance it moves. In other words, you cannot calculate the force because you cannot calculate the work. Finally you cannot calculate the kinetic/potential energy because the velocity of the mouse trap car is not constant

I have encountered many successes as well as failures when building this mouse trap car. First and foremost, I wish we kept our designs simple from the beginning instead of trying more complex and complicated designs. It would have saved us time and effort. Next, I wish we used our resources more readily at will such as the five dollars instead of trying to fix what we had. Finally, I wish we made our changes carefully and easily. We often made rash and critical changes to our car, and that put us behind schedule and ended up costing us more work. However, what I did learn victoriously was perserverance and patience, and in the end hard work did pay off.

'

Work and Power PODCAST

physics potential energy

This picture shows me going down a slide. When I was at the top of the slide I had gravitational potential energy. However, when I slid down, that potential energy was converted to kinetic Energy. If I had a mass of 27215.5 grams and I was elevated at the height of 6 meters, I could use the formula of PE=MGH to calculate the amount of potential energy.

Blog Reflection

Wow, these units are just flying by. The work and Energy unit went especially fast, but we learned many interesting and very helpful as the semester goes on. We began this unit by introducing work. Work is defined as the effort exerted on an object to change its energy. In particular Work is defined as Force x Distance and is measured in joules. To do work the distance and force must be parallel, so if walk down the hall carrying books, you do not do work on the books but if you lift the books you are doing work on them. Next we learned about power. Power is defined as the amount of work done per time required to do it. Its formula is Work Done/ Time. To compare work and power, take running and walking up the stairs. You do not do more work if you walk up the stairs or run up the stairs since both times you weigh the same and travel the same distance. However, if you run up the stairs you have more power since you do the same amount of work during a shorter time period.

The unit moved on to discuss mechanical energy. We first discussed potential energy. Potential energy is energy that is stored and held in readiness. For example a rock on the ledge of a cliff has potential energy. This particular potential energy is called gravitational potential energy because it is in an elevated position. It is measured by weight times height or PE=mgH. When the rocks falls, however, the potential energy is then converted into kinetic energy. Kinetic energy is the energy of motion. It is represented by the formula KE= 1/2 mv^2. The change of Kinetic energy is equal to the work, in fact.

Next We learned about the conservation of energy and machines. The law of conservation of energy states that Energy cannot be created or destroyed it may be transformed from one form into another, but the total amount never changes. So if there are a hundred joules of energy to begin, there will be a hundred joules of energy to end with, though some of it may be converted into heat. Machines manipulate the law of Conservation, by increasing distance to decrease the force required so that beginning work equal the end work. For instance, take the lever. The lever increases the distance so it requires less of a force to move the object. However, it is important to note that no machine can multiply work or energy. With this principle that egyptians built the pyramids, and Physics class was able to move a car!. However, with machines we concluded with learning about efficiency. It is very important to note that their is no machine that is 100% efficient which means that 100% of the energy input equaled the energy output. This is impossible so far because some of the energy is always converted into heat or thermal energy. You can calculate efficiency by useful work output over total energy input. '


All in all, this unit was gradually easier for me. I still struggle with understanding the mathematical reasoning of change in kinetic energy but I am getting better and better with it. I enjoyed this unit because it was simplistic in definitions and straightforward in formulas. I like how it all interconnected.