Mouse Trap Blog

TIME: 2.56- 1st PLACE 1. In the mousetrap car all three of Newton’s laws apply to the reason this car works. Newton’s first law states that an object in motion will remain in motion until an outside force is exerted upon it. When first placing the mousetrap car in front of the starting line, the cart would not go unless an outside force was exerted upon it. The outside force was ones hand pushing down the mousetrap, so that it would be set into motion. Newton’s second law states that mass are indirectly related to acceleration and directly related to force. Therefore, a=fnet/mass. This law affects the car because if your car has a lot of mass the acceleration will be smaller. This law changed our perspective on how to build the car and caused us to have a very light car in order to increase our acceleration. Newton’s third law states that for every action there is an equal and opposite reaction. One way that this is seen in our car is that the action is that the wheels push ground backward and the reaction is that the ground pushes wheels forward. 2. The two main places where friction was necessary was the tape put on the axel to connect the wheels and axel. In order to have a successful car the wheels need to be securely put on. The other place, was adding the rubber to the back wheels. This applied friction from the wheels to the ground. However, if you put balloons on both the front and back wheels there would be too much friction and the car would not go fast at all. 3.We decided to use four wheels because we thought it would make the car very stable. We used CD’s for each axel. We thought that CD’s would be a good medium instead of small wheels or records. Big wheels, such as records are very nice because they cover a very large distance per rotation. However, because they are so big it takes a longer time to complete one rotation than a smaller wheel would. And contrasting large wheels, smaller wheels move very quickly but have to rotate more times to get to the finish line. Therefore we found that CD’s were a nice middle ground. 4. The conservation of energy is a law that states energy cannot be created or destroyed but can be altered from one form into another. Kinetic energy is the amount of energy a moving object is capable of doing. Kinetic energy=(1/2)mv^2. The change in kinetic energy is equal to potential energy that was stored in the spring. Potential energy is the energy that is stored and held, it has the potential to do work. Therefore when we pulled the mousetrap back it had potential energy, because it was at a standstill and the energy had not yet turned into kinetic energy. When the mousetrap car began to move it was using the kinetic energy. As the mousetrap moved we know that the energy was not or gained because the conservation of energy law. 5. Our lever arm was not particularly long. Because we wanted speed and power we made a shorter lever arm in order to create more torqueIf we were building a mousetrap car that needed to travel a very long distance then we would have a longer lever arm so that more string could wind around the drive axel so that the vehicle could be pulled further. By changing the length of the mousetrap’s lever arm you are changing the pulling force, longer lever arms have less pulling force than smaller lever arms. Therefore the torque is the same therefore a shorter lever arm would then have more force. 6. Rotational Inertia is the property of an object to resist changes in motion. The more mass the object has the harder it is accelerate. Because we used a small lever arm our rotational inertial of the lever arm rotated more quickly. Also, if the mass is closer to the axis of rotation than it is easier to spin because it has less rotational inertia. Two things that we did to our car to make it have less rotational inertia is 1. We made it very light and narrow, because the mousetrap was our body, rather than using a cardboard box or wood. 2. Our wheels were solid rather than hoops making the mass pretty close to the axis of rotation making them easier to rotate. Rotational Velocity is the time it takes for 1 rotation, or number of revolutions in a certain time period. Because our wheels were relatively small they had a larger rotational velocity than records for instance. Tangential Velocity is the distance covered in a certain amount of time. Because our wheels covered the five meters will a very fast speed they have a high tangential velocity. 7. You can’t calculate the amount of work the spring does on the car because in order for you to calculate work the force and distance must be parallel. You cannot calculate the amount of kinetic energy because it is unknown whether or not the velocity is constant. And in order for you to calculate the potential energy you have to know the change in kinetic energy. You cannot calculate the force because work=(force)(distance), and in this equation both the work and the force are unknown variables. Reflection A. For the most part our original design was very similar if not exactly like our first plan. There were only a few tweaks. The first tweak was that we were originally going to drill holes in the body of a pen to put the string threw, but because our eyehooks were so small we had to use a smaller axel. We ended up using the inside of a mechanical pencil. One other small change was that we used tap to attach the wheels rather than balloons. Other than that our design remained the same. B. Our car ran very smoothly. The only mechanical error we had was when our lever arm got stuck; we solved this problem by not setting the trap but rather manually holding it down. C. I wouldn’t do a single thing differently. Our car was miraculously successful and I am very proud of the work we put into it.

   

Energy Unit Blog

We began this unit with work. work=(distance)(force). work is the effort exerted on something that will change its energy. The heavier the item the more work is being done. Two things that you must look out for is 1. when you push a wall and the wall does not move you are not doing work on the wall. 2. the force must be parallel to the distance in order for work to be done. For example when a waiter brings you drinks on a tray the force and the distance are not parallel therefore there will be no work done. 
next we talked about power. Power is the measure of how fast work is done. power=work/time. 
*the unit for power is watts and the unit for work is jouels

We then learned about mechanical energy. Mechanical energy is the energy die to the position of something or the movement of something. Mechanical energy can be in the form of potential, kinetic or the sum of the two energies. Potential energy is the energy stored and held in readiness, because it is stored and has the potential to do work. Potential energy=(mass)(gravity)(height).
Next we learned about kinetic energy. If an object is in motion it is capable of doing work and has energy of motion or kinetic energy. kinetic energy=(1/2)(mass)(velocity). 
The change in KE=work. the conservation of energy is that energy cannot be created or destroyed but it can be transformed from one form into another but the total amount of energy never changes. We then went over machines. A machine is a device for multuplying force or simply changing the direction of force. The machine goes with the conservation of energy concept. to solve a machine equation you use the formula: work in=work out, (force)(distance)in=(force)(distance)out. When dealing with machines its important to also focus on their efficiency. In order to figure out what their effeciency is you use the equation: effeciency=useful energy out/total energy output. 

the hardest section in this unit was kinetic energy. I just had a difficult time processing the formula and especially when it was the change in kinetic energy. I overcame this by doingn the examples in the book and asking mrs lawrence for help. 

My effort towards class is pretty consistent and I feel that I am a persistent participant. I also go in early when I feel that it is necessary. And my effort is reflected in-group work especially, which is a time that I am fully involved with the activities. I do my homework almost every night. The only time I didn’t was when I was not clear on the assignment. I always try to find real life videos and then explain them instead of having a video teach you the lesson, I feel as though this reflects that I am dedicated to having an engaging blog. By going in early and asking questions in class I feel that I have strong communication. And my creativity was reflected when making the podcast, and how my partners and me would use real life examples and then further discuss them. My goal for the next unit is to make sure I study before each quiz and go in early to be tested on my knowledge of that particular unit

There are many in connections this unit to everyday life. This unit applies to all things that use energy, cars ramps and even  walking up the stairs. I think that walking up the stairs is the biggest connection becayse we all do it all day everyday and it is interesting to know that if you reallly booked it up the stairs you could produce a horsepowre. 

Picture: Machine

This picture represents and inclined plane or machine. An inclined plane does not reduce energy, but rather causes you to use energy efficiently. For example a ramp on the back of a truck does not reduce the energy (energy stays the same) but reduces the force. It reduces the force because it increases the distance--> (D)(f) or (F)(d). when solving these types of problems you use the equation work in=work out, or (f)(d)=(f)(d). If we were to solve a problem lets say that the ramp is 4m long, and the height is 1m heigh and the force is 400N. you would then say...
work in=work out
(f)(d)=(f)(d)
(4m)(f)=(400)(1)
4f=400
f=100N