Joustrap Car Final Report Blog

Egg Joust Project

Kristian Fadrigon, Ellis Sutton, Eric Alipio

Period 4

Physics

Mr. Yav

The Trapper

Table of Contents:

1. Introduction
2. Design
3. Construction Procedure
4. Operation of Mousetrap Car
5. Results
6. Conclusion/Improvements
7. Appendix

Introduction:

The purpose of this project is to demonstrate the property of conservation of energy, as it is transferred from elastic potential energy to kinetic energy. To demonstrate this, we must construct a mousetrap car that will travel a distance of 1.5 meters in the shortest amount of time. Additionally, the conservation of momentum will be observed as different groups’ cars come crashing together.

Design:

In coming up with the design of our mousetrap car, there were several variables that we had to take into account. These variables include the size and type of the wheels, the wheel-to-axle ratio, the weight of the car, and the length of the snapper arm that pulls the string. In our initial brainstorming session, we opted for a decently-sized body with a smaller wheels and a longer snapper arm, which would also be used as a weapon for the joust portion of the project. We were also thinking of using a ramp to alter the direction of the opposing vehicles, but we decided to use a piece of cardboard and attach it to the end of the snapper arm that acted as a shield from the opposition's offensives. We chose small wheels because that allowed more rotations and thus a faster speed. The wheels we chose were rubber KNEX wheels that had a lot of friction, resulting in greater power and spin efficiency. We also decided to use a long snapper arm so that it disperses energy it one smooth, long pull, allowing for a greater distance. The body itself was constructed out of wood, which made our vehicle somewhat heavier than what is ideal, but we thought that we could balance out the weight by optimizing the conditions for the other variables, such as the snapper arm length and the size and type of the wheels. The following materials were used in the construction (bold indicates the item was found at home and its estimated price is listed):

Material	Price	Name
Mousetrap	$1.98	Kristian
Wood	$6.00	Ellis
Snapper Arm	$.50	Kristian
Wheels	$2.00	Eric
Axle	$3.99	Ellis
String	$3.99	Eric
Adhesive	$4.00	Eric/Kristian
TOTAL PRICE: TOTAL SAVINGS:	$9.96 ($22.46 total) $12.50

Construction Procedure:

1. To begin, we cut out 3 pieces of plywood. The first piece (the main body) is a by 10 cm large cut out. The 2 other pieces (the sides) are identical that have the dimensions of 25 by 3 cm.
2. Secondly, we nailed each side piece to the long sides of the main body.
3. Before we secure the mousetrap to the car, we removed all pieces that were not the spring or the lever.
4. After, we nailed the mousetrap all the way back and to the right side of the body.
5. Next, we duct taped a long, skinny rod to the lever in order to lengthen the pulling of the string.
6. 3 inches from the tip of the rod, we taped a small cardboard cut out on to the rod as a shield.
7. And then, we drilled 4 holes equidistant on the front and backside of the side pieces.
8. We placed 2 skewers through the holes and capped each side of the skewers with our 4 KNEX car wheels.
9. Lastly, we attached the lever of the mousetrap to the back skewer with a long piece of string.

Operation of Mousetrap Car:

Our mousetrap car works by the lever pulling the string which pulls the back skewer (the axle) and its wheels. Since our lever was extended by a long rod, the length at which the string is pulled is also extended, increasing the overall distance our car could achieve. When we pulled back the lever, potential energy was created. Once we let go of the lever, kinetic energy was released. Similarly, our 4 inch in diameter front wheels allow them to have more rotation and thus more speed than our back wheels. Our back wheels, being 6 inches in diameter, allowed our car to travel greater distances because it took longer rotations with less power needed. The big wheels in the front had more friction acting upon them as they had more surface area and more mass, causing our car not to travel as fast as possible. Since our car was made of wood and our parts were fairly bulky, we gained more momentum as our car moved because of its mass and increasing velocity. This allowed for a greater impact as it hit the other vehicles. To help minimize the change of momentum or impulse we added the shield which would dampen the impulse since the shield would bend slowing down the car.

Results:

Our car performed well for our first jousts, but the string and the back axle got caught, This caused our car to malfunction and not start the joust, resulting in us moving to the losers’ bracket. We ended 5th in the tournament. Our car’s acceleration was 0.2739 m/s2. We got this result from our time interval race, in which our car traveled 1.5 meters in 2.34 seconds. Our egg did not break during the joust, however it did fall out.

Conclusion/Improvements:

Overall, our design was solid, however the use of materials and execution wasn’t as so. The parts we would have kept in our design would be the wheels, the egg holder, and our makeshift shield. These three things worked well in winning our first jousts. However, we would have used stronger axles and a stronger lever. The axles, we could see, especially the back axle, we bending greatly which could have affected the friction against the rest of the car. The lever also bent a great deal. Since it bent back so much, this could have changed the speed or force at which the lever pulled the wheels, greater affecting the car as a whole. Also, we would have sanded down the edges and cut out any extra, unneeded wood so that the string wouldn’t have anything to get caught on and the car would accelerate faster due to the weight being decreased. This would also allow the car to start faster.

Appendix:

Our final vehicle

Our final vehicle (fully extended)

Our first victory over John W's group

Our second victory over Luigi's group

Our first loss to David's group

Our second loss to Drew's group when our car failed to start

Egg Joust Project Preliminary Design Report

Egg Joust Project

Eric Alipio, Ellis Sutton, Kristian Fadrigon

Mr. Yav

Physics - Period 4

January 29, 2016

Executive Summary:

The purpose of this project is to demonstrate the property of conservation of energy, as it is transferred from elastic potential energy to kinetic energy. To demonstrate this, we must construct a mousetrap car that will travel a distance of 1.5 meters in the shortest amount of time. Additionally, the conservation of momentum will be observed as different groups’ cars come crashing together.

Table of Contents:

• Design Problem and Objectives
• Detailed Design Documentation
• Test Plans
• Bill of Materials
• Task Chart
• Safety and Ethical Consideration
• References

Design Problem and Objectives:

There are two parts to the egg joust project. The first part consists of building the mousetrap car so that it travels a distance of 1.5 meters in the shortest amount of time, or in other words, build a car with the fastest acceleration. On top of the car, we will place an egg which will act as the “driver” of the car. The second part of the project involves improving upon the already built car by adding tactical offensive and defensive weaponry. Two cars will be placed on opposite ends of the ramp and will face off in a jousting match. The objective is to knock the opponent’s egg off their car. There are several limitations. On the car, sharp objects like knives or skewers, explosives, or bear traps are not allowed. Dimensionally, the car cannot exceed 20 centimeters in width and 30 centimeters in width.

Detailed Design Documentation:

The rotation of the wheels and the wheels themselves play an important part in how our mousetrap car will function. If our wheels are large they will require less spins to travel a greater distance. However, with smaller wheels, the smaller circle means more rotations and thus greater speed. In order to get these wheels moving, the energy of tension and springs is released to spin the wheels, propelling the car forward. When the spring is released, the string attached to the end of the spring’s arm will pull the axle, causing the wheels attached to the axle to spin. The length of the spring’s arm determines whether the car will gain more distance or more power. The longer arm will disperse the energy across its pull, allowing for a longer pull and overall distance. A shorter arm will release the energy in one quick jolt, creating a larger amount of power in a short amount of time. This will cause the wheels to spin faster and create more power. Friction is a major factor in the creation of our mousetrap car, as it can decide whether or not our car will be a success. The more surface area a wheel has, the more friction we can get, resulting in a greater power and spin efficiency. However, if the body is too heavy, this can also increase our friction, resulting in the car having a slow ride. Likewise, if the axle has too much friction, than the car will have a harder time accelerating and gaining power. That being said, the best way to get power is to reduce the bad friction (friction due to too much weight or axles) as much as possible so that the vehicle can accelerate as fast as possible and as smoothly as possible. To keep our rider, an egg, from perishing during the ride, we must create a greater crash zone. The front or the chassis will absorb the momentum change during impact by crumpling in front of the egg, instead of crumpling around the egg. While keeping our egg safe, we will use a ramp to flip our opponent and attach a blunt object to the swing’s arm to crush the advancing mousetrap car.

Since a lot of our materials are from home, we expect to no more than $10 on this project.

The human factors that could make our car be successful or a failure may be in the way we build it. If we build the mousetrap car too short or too long, it can affect how the car performs. Therefore, we must be careful with our measurements and calculations (if any).

• Whiteboard brainstorming session:

Test Plans:

After we build our car, we plan to test using wheels of different sizes and traction levels. For example, we might test our with Lego Wheels vs. CDs. Although the surface we are executing the project on is the floor of the classroom, we plan to test on other surfaces too, like concrete, hardwood, carpet, etc.

Bill of Materials:

Material	Price	Name
Mousetrap	$1.98	Kristian
Wood	Already Have	Ellis
Snapper Arm	Already Have	Kristian
Wheels	Already Have	Eric
Axle	$3.99	Ellis
String	$3.99	Eric
Adhesive	Already Have	Eric/Kristian
TOTAL PRICE:	$9.96

Task Chart:

Tasks	Kristian	Ellis	Eric
Bring Materials	X	X	X
Write Blog	X	X	X
Compile Blog	X
Turn In Blog	X
Build Car	X	X	X
Bring Car			X
Test Car	X	X	X

Safety and Ethical Consideration:

We did not use any weapons that would be harmful to ourselves and our classmates including but not limited to knives, scissors, screwdrivers, tweezers, etc. We bought wood pre-cut or had an adult make alterations to the dimensions of the wood to avoid harm to ourselves. We are exposing the egg properly to avoid any unfair advantage for our group.

References:

• joustrapcar2015-2016.pdf - template for engineering design goals

Rocket Project Lab Report

Kristian Fadrigon

11/6/15

Period 4

Rocket Project Lab Report

Materials and Approximate Price:

• Two 2-liter soda bottles ($1.79 each)
• A pack of cotton balls ($0.97)
• A pack of rubber bands ($0.49)
• Duct tape ($2.00)
• Scissors (no purchase necessary)
• Cardboard (no purchase necessary)
• Garbage bag (no purchase necessary)
• Single-hole punch ($0.91)
• Parachute cord ($4.88)
• A piece of paper (no purchase necessary)
• One egg (provided)
• A rocket launcher (provided)
• Total amount spent: $12.83

Procedure:

1. First, acquire all the listed materials. 
2. Cut off the bottom of one of the soda bottles. 
3. Using the duct tape and the piece of paper, make a cone about half the height of the bottle and secure to the top of the bottle, making the nose of the rocket. 
   
4. Next, cover the walls of the inside of the rocket with cotton balls about two layers thick.
5. Leave a space in the middle for the egg to be placed.
6. Take a few rubber bands of similar size, and attach them to the inside of the rocket, forming a cross above where the egg will be placed. 
7. To make the parachute, first cut the parachute cord into five pieces of equal length, preferably around 1-2 feet.
8. Cut out a circular piece from the garbage bag and hole punch five holes equidistant along the circumference.
9. Tie one end of the parachute cords to each of the holes, and tie the other ends together. 
10. Attach the conjoined ends to the rubber band cross inside of the soda bottle. 
11. Fold the parachute neatly so it fits comfortably in the passenger compartment of the rocket.
12. Next, cut out five fins for the rocket using the cardboard, with three fins for the fuselage of the rocket and two fins for the passenger compartment of the rocket. 
13. Attach the fins to the rocket.
14. Take the untouched soda bottle and place it in the opening of the passenger compartment of the rocket.
15. With the rocket completed, test the rocket to ensure the parachute deploys properly.
16. On launch day, fill a quarter of the untouched soda bottle with water. 
17. Place the egg in the passenger compartment.
18. Again, carefully fasten the two bottles together as to not prematurely break the egg.
19. Place the fuel bottle of the rocket onto the launcher. 
20. Pump the air in the launcher to about 70 pounds per square inch.
21. Countdown from three and pull the string that launches the rocket.
22. Observe its height and record the time it takes to reach its apex.
23. Once the rocket lands, check to see if the egg survived. 
24. Record your results.

Results:

Unfortunately, our group's rocket did not work the way we thought it would. Compared to the rest of the class' rockets, our rocket achieved a relatively low height of around 45 feet, and the time it took to reach the top of its trajectory was only 1.78 seconds. Additionally, the passenger compartment of the rocket did not detach and the parachute did not deploy, leading to the untimely demise of our "eggonaut." However, this was not surprising, since about half the class' parachutes did not deploy even though their rockets flew higher. One thing that I noticed as our rocket was in mid-flight was how heavy the rocket looked. Flying through the air, rocket looked as if it was unable to go higher than it did because of the amount of duct tape we used to make and secure the nose and fins of the rocket. The weather was ideal for flying, so I think no other factors contributed to the inability of our rocket to work except manufacturing errors. 

Conclusion:

In hindsight, there are several things I wish we had changed about the design of our rocket. First of all, I would have changed the size of the rocket's nose and the amount of tape used to secure it. I believe the weight of the rocket came mostly from the passenger compartment, especially the nose. If we had reduced the weight in the passenger compartment, our rocket definitely would have risen higher and faster to its peak. I would also change the fins from cardboard to something thinner and lighter, like plastic. On the inside, I would have put more cotton balls to soften the blow to the egg when it reaches the ground. Although we thought the rubber bands would act as a shock absorber when the rocket impacted the ground, that was only if the parachute properly deployed, which it did not. Overall, if I could do anything to make our rocket better, it would be making it lighter and slimmer.

Calculations:

Force Body Diagrams:

Video of Rocket Launch (Takeoff is around 1:17):