Evidence of Work

Our task was first to create and make our own car. Then, we would find the forces acting on it when rolling it down a ramp. Then, we went even further by seeing how fast it could go by adding external forces. My group started out by making a car using a wood block, wooden sticks as wheel axles, and then washers as the actual wheels. We had to glue the washers to the axles because they kept sliding around and falling off.

Our next step was to find the force of static friction on our car. We did this by gathering the mass (0.5kg) and then using a wooden ramp, finding the angle that it would begin to move at when tilted. From there, we could use the force of static friction equation to find our static friction coefficient.

Our final step was to gather the information and data needed for the project. We found a ramp with as little extra friction as possible (smooth) and then we set up our testing. Our group did more than other groups in terms of variables because not only did we add external forces, but we also changed the angle that the ramp was placed at. We placed the ramp at angles of 10, 20, and 30 degrees and then we added the external forces. These included an added mass (+0.075kg), a string pull, and a rubber band launch. Since we were testing for what would make the car go the fastest, we tested for acceleration. Our final conclusion was that the string pull gave the highest acceleration of our car and therefore made it go the fastest. We gathered all of our results and put them into a presentation. The slideshow is below and goes into more detail for each of our tests and trials.

Content

Here are a few important concepts explained in detail that were used throughout this project.

Velocity

Velocity is another word for speed. An object's speed can be determined by it's change in position (or distance traveled) divided by the change it time (time it took to travel that distance). This can be represented by the equation: v=d/t or v=x/t (velocity equals distance/displacement divided by time). The remaining answer will be in the unit of meters per second.

Acceleration

Acceleration refers to how fast an object is speeding up or gaining speed. This can be determined by taking an object's change in velocity from start to finish of a certain distance or time frame and dividing it by the time it took to travel that distance or for by how long the time frame was. This can be represented by the equation: a=v/t (acceleration equals velocity divided by time). The remaining answer will be in the unit of meters per second squared, also known as meters per second per second.

Gravitational Acceleration

Gravitational acceleration refers to an object's free fall acceleration, also known as acceleration due to gravity. Gravitational acceleration can differ from between masses and have a different value on different planets or different stars, etc. The gravitational acceleration on Earth is equal to 9.8 meters per second squared, and it is a value of acceleration.

Forces

Forces on an object can be defined as what is setting an object into motion or what is moving/not moving an object. Various forces can act on an object and they can act in multiple directions. Some common forces are the gravitational force, the normal force, and the frictional forces.

Gravitational and Normal Forces

Gravitational force is present on any object that has mass. The force of gravity will pull objects towards its center and on Earth, this happens at a rate of 9.8 meters per second squared. Objects will always fall with the same free fall acceleration, but can have different gravitational forces. The gravitational force of an object is equal to an object's mass times the gravitational constant, which is 9.8 meters per second squared (Fg=mg).

The normal force of an object is what pushes up on an object when it is on a surface. The force of gravity and normal force are always equal in magnitude when an object is at rest. Force of gravity is also always pointing towards the center (of the Earth), but the normal force is always perpendicular to the surface that an object is on. This means that if the surface is an angle, the normal force will also be at an angle.

Frictional Forces

Frictional forces are forces that either keep an object from going into motion or slow an object down that is already in motion. This is the force of objects on a surface touching that surface, and in free fall, air resistance. There are three types of frictional forces: static, kinetic, and rolling, but the main one used for this project was static friction. Static friction refers to an object's friction when sliding across a surface. The static frictional force's magnitude of force can change, but the coefficient of friction will always remain the same. To find the coefficient of friction, use the equation: Ffs=Us * FN (force of static friction equals the coefficient of friction times the normal force). The remaining answer will not have any units since it is just a coefficient.

Tension

Tension is usually referred to and used as the 'pull' of a string or other wire, cord, elastic, etc. It is the force of that string or other material between two objects that are exerting a force on it. There are many different ways to calculate tension, but the forces of the two (or sometimes more) objects must be known or used as variables. Tension was used in this project because of the string pull and the rubber band launch. For our purposes, we did not calculate the exact force of tension on our car from the string, but we knew and showed how it was a contributing factor in the increase in acceleration of the car across the ramps of different angles.

Reflection

For this first semester of AP Physics, I have really enjoyed the projects and learning about the new concepts. It has also been a struggle for me, as wrapping my head around some of the topics has proven very difficult and time consuming for me, and some I still do not fully understand. Two areas where I think I did well this semester were communication and collaboration. For communication, whenever I needed help with either the project we were working on, the concepts, or anything else, I would make sure I went and asked for it, either from Mr. Williams or my group members if I could. For collaboration, all of my group projects turned out pretty well in my opinion, and I was able to communicate and collaborate with my group members to get things done well and on time.

Two areas where I struggled may have been in the critical thinking and conscientious learning areas. For both of these, I feel like I am part way there on achieving them, but not one hundred percent yet. For critical thinking, AP Physics has had lots of very difficult material, and sometimes I feel like I need to focus more on one topic at a time to understand it and move on to the next to connect all the dots. Using my critical thinking skills more in this class should hopefully help me succeed in understanding more of the material to a greater extent next semester. For conscientious learning, sometimes I feel like I am making the same mistakes over and over again, and spending time understanding what I have done wrong and studying how to do better next time would probably be very beneficial for me, especially leading up to the AP exam. Overall, I feel like I have done pretty well in this class, and hopefully next semester, I can outdo this semester and do even better in AP Physics.