A) x=20cos(8.6°)t
y=-16t²+20sin(8.6°)t+1.5
B) x=47cos(17.46°)t
y=-16t²+47sin(17.46°)t+3
C) x=64.15cos(26.74°)t
y=-16t²+64.15sin(26.74°)t+4.5
D) x=69.167cos(36.87°)t
y=-16t²+69.167sin(36.87°)t+6
E) x=71.43cos(48.59°)t
y=-16t²+71.43sin(48.59°)t+7.5
F) x=66.18cos(64.16°)t
y=-16t²+66.18sin(64.16°)t+9
This project was based off of a set of instructions that we were given. We built the machine according to the instructions and constructed a device to launch a ping-pong ball. We then collected data from different launches (height, time, distance, angle) and created parametric equations to match the data. The equations we created were: Below is a picture of the graph of the above parametrics. It shows the paths taken by the launched balls.
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In this lab, we were given marbles of three different materials: wood, plastic, and metal. We were then challenged to sort the marbles by material using only materials contained in the VEX kit. Initially, we had intended to use a line follower to sort the marbles, which detects differences in color and light. The line follower proved too unreliable and difficult to work around, however, so we ended up just using physics. We used two motors: one to feed the marbles in and another to tilt the second ramp (first one from the left in the side view). Using a simple looped code, the feed would drop a marble. If it was metal, the weight would make it drop straight down into the first box from the right. The plastic and wood would continue moving on to the second ramp. The second ramp was set to tilt down to the right (based on the side view above) after a short period of time. The wood moved slower than the plastic, and so would be tipped back with the ramp, falling into the Chapstick container. The plastic would just blow through and fall into the large blue box on the end.
In this lab, we were challenged to build a fully-functioning elevator with three floors. It needed to be able to be summoned from each floor, return to the ground level after a period of inactivity, and have an override switch to bring the car back down to the ground. It also needed to have LED lights to indicate which floor the elevator was currently stopped at. We used a sonar to determine the height that the lift was at. Once it reached the height indicated by the button pressed, the motor stopped. The red light indicated that it was on the top floor, the yellow that it was on the second, and the green, visible in the front view, indicated that the lift was on the bottom floor. We had issues with our sonar reading correctly, and so we had to adjust its measurements and values for each day of coding. The coding was the most difficult part of the project. The code had to be clearly organized in order to tell exactly what function fell under which if statement. We ended up having if statements within if statements, and at one point, our font size was so small it could hardly be read. In the end, however, we got the elevator to work. The little green things that served as our chocolate in the cookie topper lab were out passengers, and they could reach any floor at any time they wanted.
The purpose of this lab was to design a machine that would feed "Cookies" (wheels, in this case) and drop "chocolate" (little green connector things; we aren't sure of the name) onto the cookies. The hardest part was designing a system to feed the cookies onto a conveyor belt, as the cookies got stuck on one another. In the end, we set them on a ramp and used a rubber gear to feed the cookies on the belt. Though not visible in the above images, two lights (one red and one green) are located in the middle. The red light is on while the belt is stationary, while the green is on while the machine is operating. The program starts when the bump switch is pressed, starting both the motor that drives the conveyor belt and the motor that feeds the cookies. Once a cookie is within 137 mm of the sonar, the belt stops and chocolate is dropped, utilizing another motor. The belt moves on, and the process starts over again. The hardest part of programming the robot was setting the correct distance for the sonar, as if the distance was too short, the chocolate would miss the cookie, but if it was too long, the chocolate would drop just because the belt moved.
This project consisted of constructing circuits in a University of Colorado PHET Simulation. We were instructed to create two circuits in the program.
So, the total resistance for the second circuit is 10.718 Ohms. The current can be found by hand by dividing the voltage by resistance, so the calculated current would be 1.399 amps. In a parallel circuit, the voltage is all equal and consistent.
The Bridge Design Contest has started up again! This bridge uses a mixture of Quenched-and-Tempered Steel and High Strength Low-Alloy Steel of varying widths. It also utilizes arch abutments. The cost of this design is $175, 169.12.
For this project, the group built a test bed out of VEX components. We then worked on the basics of ROBOTC programming. We learned how to work the motors and servo, as well as the functions of the various digital and analog sensors.
In a program named West Point Bridge Builder, the user is challenged to make a stable bridge for the lowest cost possible. My lowest has cost $184,293.23. It is made up of a combination of carbon steel and quenched and tempered steel bars and tubes and was built at a height of four feet using arch abutments.
This lab required us to make a self-propelling vehicle go 28 feet. The original constraints allowed for no ramps and nothing left behind save a counterweight. The group, however, had an original and creative idea, and the instructor allowed us to leave behind the majority of our mechanism. With a single axle, we had issues making our vehicle run straight every time, but guide walls along the ramp and chains used to make sure the ropes were centered helped solve the issue. In order to create motion, we wound a string around the center of the axle, which is connected to a chain and counterweight. When released, the counterweight causes the string to unwind. The vehicle drops and continues the motion, kind of like a yo-yo.
In this lab, we were challenged to make a vehicle that could propel itself a total of 20 feet, completely free of human force. Originally, our design had an insanely large mechanical advantage, but it required too much force to propel, so we decreased the IMA and increased the weight of our counterweight. We didn't actually make it the distance of 20 feet, with our maximum distance lying closer to 10 feet.
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