Fire away
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Alternative energy vehicle
Evidence of Work
Fire Away (Trebuchet)
Machine
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Top
Side
Our Design: Our goal was to make a trebuchet that could launch a projectile farther than anyone else. Although this may not have been achieved we still made it to around 30 meters for each test. We decided on an arm that was longer in the back because it allowed us to launch our projectile at a greater angle. We also decided to use springs as opposed to rubber bands due to the fact that they can handle more stress and tension. We tried various other designs and modifications, but in the end, this is the one that yielded the best results.
Selling points: It is a simple design that is not very difficult to reconstruct, you can use 2 moderately sized springs instead of tens of rubber bands, and we use a non-wooden axle to reduce friction.
Modifications:
Axle raised higher off ground- more PE can be utilized to turn to KE
Greater pre-launch angle- this allows for more pullback/tension which results in more equaling a greater distance launched
Arm length to axle ratio- we made the side launching the object longer so that it could convert more PE to KE resulting in a greater distance
Using a smaller projectile- The smaller the projectile the less air resistance it would take
Using a lighter projectile- the less mass the greater the acceleration would be
Using a lighter arm- More PE is converted to KE resulting in a higher velocity and velocity distance.
Content
Time in air- 3.5s
Angle of release - 63*
Horizontal distance- 30m (98.42 ft)- Amount of space between 2 points on the horizontal plane
Vertical Distance- (d=1/2a t^2) where t is the fall time=15m (49.21 ft)- Amount of distance between 2 things on the vertical plane
Mass of ball / projectile- 10g=0.01kg
Vertical velocity- (v= at) - 17.15m/s - Velocity of falling object going up or down
Horizontal velocity - (v = d/t) - 8.57 m/s - The average speed on a flat surface assuming no outside force\
Total velocity- 19.15 m/s - The horizontal and vertical velocity combined using a^2+b^2=c^2
The kinetic energy of the ball (KE = 1/2 m v^2)= 1.83J - energy due to motion
Spring constant ( k=F/d) = 1,100 N/m
Initial spring potential energy ( PE spring = 1/2K x^2) = 19.86 J
Percentage of energy converted (KE/PE) = 9%
Reflection
During this project I think the group I was a part of excelled in collaberation and creation of our trebuchet. I feel that I did a good job at leading the group in creating and modifying the machine. The project had a rocky start with us lagging behind, but we eventually caught up and were on par with everyone else, As a group we worked very well together and were always on task. I feel that in the more hands on projects I tend to mess around and procrastinate less and do more of my work on time or even before it needs to be turned in. Some of the things we could have improved on was moving past just using springs and maybe inquiring about others ideas more often. We probably could have managed our time better and learned from the other groups around us. Overall, it was a pretty good project to work on a good group to work with.
Alternative energy vehicle
In-depth slide show/explanation
Quick slideshow
In this project we mad a vehicle that consistently traveled 5 meters while using a source of reusable alternative energy. We created multiple graphs on how the energy was converted and the relationship between distance and time, velocity and time, and acceleration and time. We created a vehicle that had low friction which allowed to travel quicker and more efficient. Our cost of the vehicle was low and affordable and our ramp's height was 33 cm tall.
Content
Gravitational Potential Energy: Energy an object has due to its height or position in a gravitational field. We found the PE of our vehicle before it was released from our ramp and graphed how it changed as time increased
Kinetic Energy: Energy due to motion. We found the KE of our vehicle as it traveled the 5m and graphed its relationship to time.
Total Energy: We found the Total Energy by finding the PE before the vehicle is released. The total energy stays the same throughout the entire 5m and is shown in our energy vs. time graph.
Thermal Energy: Energy lost to heat. We found thermal energy by subtracting PE and KE from the total energy. We found the thermal energy at each meter mark and graphed how it changed over time.
Distance vs. Time: We made a graph showing the relationship of distance and time and how they changed based on eachother.
Velocity vs. Time: We made a graph showing the relationship of velocity and time and how they changed based on eachother.
Acceleration vs. Time: We made a graph showing the relationship of acceleration and time and how they changed based on eachother.
Rotational inertia: Rotational inertia says that something rotating will not stop rotating until stopped by an outside force. We learned that the Conservation of the rotational momentum is Iw with I being the moment of inertia and w being the rotational velocity. With the vehicle and wheels we moved the mass into the center because that decreases the moment of inertia and then resultantly increases the rotational velocity.
Reflection
During this project I felt that we all did a good amount of work some more than others but we each helped where we could. Some things that I think we exceeded in though were our collaboration with each other and calculations. We all worked hard but worked but quick and efficient. For us the project was done fairly quickly so we had a lot of free time to discuss what we had done and work on how to improve upon what we had already finished. 2 things we probably could have worked on was talking with each other more and for me not procrastinating but being on task and listening to others. In the end I feel this is one of the best groups I have worked with this year.