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