Joustrap Car Final Report

Kyle Macauley
Devon Buenrostro
Ricky Pearce
2.29.16
Mr. Yav
Period 5
Physics
TRAPDAT

Table of Contents:

Introduction
Design
Materials
Construction Procedure
Operation of Mousetrap Car
Results
Conclusion/Improvements

Introduction:

We were tasked with creating a car, powered by a mousetrap, with the purpose of battling another car while protecting an egg. We were provided with a ramp and an egg, everything else was up to us. Our initial ideas differed from the finished product. Our group wanted to use CDs for wheels because of their availability and size. After researching for a day, we decided to use other materials to create our car. Many of our initial ideas were scratched after we spent time discovering the best way to create a car.

Design:
We brainstormed about the general design of our car. Things such as how heavy we wanted it to be, the materials to use, and the reality of our ideas. Our main mistake came with how heavy we made the car. Our car was very heavy due to the material we made it out of. We used thick wood in hopes that our car would destroy rival cars in the jousting competition. Our car ended up being very long (the maximum length) and very heavy. This did not work well for us. We followed the initial design we had for the car but used different materials than what we originally planned. This was partially due to availability but also a change in plans. We failed to add much padding to our car because it was heavy and there was limited space. We decided to put our driver up high and build him a cart to sit in.

Materials:

Wood - $12
Duct Tape - Free ($5)
Skateboard Wheel - Free ($5)
2 RC Car Wheels - Free ($10)
Chopsticks - Free ($.50)
Mousetrap - $2
Fishing Line - $2
Pencil - Free ($.50)

Construction Procedure: 

1. Acquire all of the materials listed above. 

2. Use a thin wooden slab to create the belly of the car. 

3. Tape/glue two thin pieces of wood sticking out past the belly of the front of the car as well as the back. 

4. Drill holes in these four pieces, we will be putting the wheels between them. 

5. Tape the mouse trap to the middle of the wooden slab.
6. Attach a pencil to one side of the mousetrap.
7. Slide a chopstick between the drilled holes in the pieces of wood, on both sides.
8. Slide the wheels on. Make sure they are on tightly. Apply tape to ensure their tightness.
9. Attach a string to the pencil and wrap it around the back chopstick of the car.
10. The car should be ready to go and look similar to the picture.

Operation of Mousetrap Car:

The car is powered by a mousetrap. As the mousetrap goes from the open position to the closed position, it pulls on a string which is connected to the back wheels. This causes the wheels to spin and the car to move. The mousetrap has potential energy when it is cocked back. As the trap moves forward, the energy is conserved and transferred to kinetic energy. The work the mousetrap does on the car allows for it to move. The car must be heavy enough to have large enough friction to not spin out. Once moving, the momentum of the car carries it until gravity and friction stop it. The energy is always conserved, but it is transferred. We wanted our car to have a large amount of force so we made it heavy. This affected its acceleration but since F = Ma, the force was still relatively large.

Results:

Overall, our car finished tied for fifth in the jousting tournament. We did not preform as well as we would have liked to but it was a good effort. Our car preformed as well as it could have with the design it had. Our egg never broke which was an accomplishment. We lost in our second joust but made it to the semifinals of the losers bracket. Due to the weight of our car, it did not accelerate quickly. We have inserted pictures of our car in action at the jousting tournament.

Conclusion/Improvements: 

As we mentioned multiple times, our car was too heavy. We would make our car significantly lighter to increase its acceleration. With the lighter car, we would need more padding for our egg. A crumple system would help prevent a strong impact on the egg. We would use plastic instead of wood to make the car lighter. Wood was hard to use and especially hard to put together with only duct tape. Plastic would be easier to work with as well as providing the benefit of weight. Acceleration seemed to win the tournament because eggs were rarely launched out of cars. Crossing the middle line first would help win many more rounds rather than attempting to break the other car. 

TRAPDAT

1.29.2016

Physics 

Mr. Yav

Devon Buenrostro 

Kyle Macauley 

Ricky Pearce 

Executive Summary:

We are going to build a car, carrying an egg, powered by a mousetrap in order to demonstrate the conservation of energy. Our car will be put to the test against another car in a jousting battle. Our goal is to build a car that can accelerate quickly and use our knowledge of impulse to protect our egg and win the battle. Our intended design will be similar to this sketch. 

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: 

We have been tasked with creating an original car that can keep an egg safe during a collision with another car. The engine of the car must be a standard sized mousetrap and the car must be made from scratch. The first part of the project is to design a car to accelerate over a minimum of one and a half meters of flat ground at the fastest rate attainable. The second phase is to go head-to-head with another car. The cars will be placed on opposite ramps and crash into each other at the bottom. The goal is to keep the egg safe throughout the process.

There are multiple obstacles in the way of creating a perfect car. For instance, it is optimal to have a light car to increase acceleration but it is helpful to have a heavier car to deliver more force during the collision. A happy medium must be met in order to successfully accomplish both goals. This means designs must be met in the middle to optimize both speed and weight. 

       Another additional challenge will be protecting the egg from collision. There will not be very much room on the car due to the condensed size to increase acceleration. We must use our space efficiency and design a crash system that will reduce the impact on the egg.

In terms of winning the battle, we are going to design a car with a low center of gravity and possibly an extension off the front to destroy the opposing car. We cannot extend the length of the car too long or it will not make it down the ramp safely because of the difference in the angles of the surface.

Detailed Design Documentation:

a.) The mouse car is able to move because of the spring in the mousetrap. The spring is the power source for the entire car. It brings the hammer of the mousetrap forward and releases energy in the process. In our design, a pencil is connected to the hammer. Connected to the pencil is a string, with one side wrapped around an axle, which spins to make the wheels spin. The energy comes from the work done by the spring. The Fspring multiplied by the distance the hammer travels results in the amount of work done. In order to create more acceleration, our design incorporates a pencil. The pencil is used to create a sixty-degree angle to maximize the force of the mousetrap. The larger the force, the faster the acceleration should be. Another method to increase acceleration is use smaller wheels. The wheels will have more rotations and the car will move quicker. We will acquire small wheels with this in mind. It is also important to have a small axle to wheel ratio. This is important because the as the axle spins, the wheel will follow sync. With wheels spinning fast, our car will need added friction to preform the best possible. We decided using balloons as added friction would be a good idea because real tires are made of rubber and balloons have a similar texture. The body of our car will not be light but it will not be overly heavy. This is for two reasons. We want to have the best acceleration possible but we also need our egg to survive the impact. Our goal is to destroy the other egg and we need some weight in our car to increase the momentum. We are also going to create a low plow extension to knock the other car out of the way. It should change the direction of the opposing car or destroy their egg. To protect our egg, we will create a sequence of padding to decrease the impact, similar to airbags. Our objective is to slow the force over as long amount of time as possible.

b.) In total we are estimating our cost to be around thirty dollars. 

c.) Human factors will be a problem when creating the car. No matter how well we calculate or design the car, there will be some error in creating it. We can minimize these errors by testing the car many times and correcting various things.

Test Plans:

We will test the mousetrap the most. We will use various angles to determine which one works the best for our design. Sixty-degrees is said to be the optimal mark but we will test various angles to prove this. We will also test different size wheels and decide how big or small we want to go. Lastly, we will test different weights of the car. We will need to find a happy medium in which the car can accelerate and also deliver a big force when it collides with another car.

Bill of Materials:

Mousetrap - $5

Balloons - $2

Fishing Line 2$

Pencil - Free

Two medium wheels - $6

Two small wheels - $3

Chopsticks - Free

Wood - $12

Task Chart:

Design Report (All) 1/29

- sections 1-3 (Ricky)

- sections 4-5 (Kyle)

- sections 6-10 (Devon)

Acquire materials (Ricky) 1/29

Build car (Kyle & Devon) 1/31

Run tests (All) 2/3

Preform in class (All) 2/5

Safety and Ethical Considerations:

We will create our car from scratch without copying anyone’s idea. We will make sure to do our own work and be safe when creating the car.

References:

www.instructables.com/id/mouse-trap-car/

www.docfizzix.com/topics/construction-tips/mouse-trap-cars/

www.wikihow.com/adapt-a-mousetrap-car-for-distance

Materials

Duct tape: $3

Cardboard (shoe box): free (shoes = $90)

2 Two liter soda bottles: $4

String: $2

Umbrella: $20

Foam (couch cushion): free (couch = $1,500)

Procedure

1. Using the cardboard from the shoe box, cut out four fins, all similar in length and width. Make them about 3 inches wide and 6 inches long

2. Duct tape them to the body of one of the 2 liter bottles. Tape them near the opening in the bottle but not too close. About 3 inches from the opening. Space them out evenly and tape them throughly. 

3. Once your fins are done and secured, cut the top and bottom off the second bottle. Cut about four inches from the top and as low as you can go on the bottom. Save all the pieces. 

4. Take the middle piece that you cut out and tape it to the top of other bottle. Tape it to the side away from the opening of the bottle. Make sure it is secure. 

5. Use the pieces of the top and the bottom of the bottle to create a capsule. Put them together and tape them together. 

6. Cut out three pieces of cardboard and tape them to the top of the capsule. Tape them in a pyramid shape and create a nose cone. 

7. Take the umbrella and remove all of the metal from it so it is just the fabric. 

8. Evenly poke 8 holes into the fabric of the parachute and tie string to these holes. Make the string about the length of the diameter of the umbrella. Make sure all of the strings are the same length.

9. Tape the loose ends of the string together. Tape this bunch of ends to the bottom of the capsule you created previously. 

10. Put foam inside the capsule and tape it shut. 

11. Fold up the parachute in an accordion fashion as tightly as possible. Wrap the string around the parachute and place the parachute in the empty container that is attached to the body of the rocket.

12. Place the capsule on top of the parachute. Do not tape it to the rocket. 

13. Place an egg in the capsule and launch the rocket. 

Results

Our rocket preformed very well. It launched very high, the capsule detached, the parachute deployed, and the egg survived. Our rocket was the only one to completely fulfill all of the requirements. Other groups got into trouble when their egg capsule did not deploy. The weight in the nose cone of our rocket allowed it to pull the entire capsule and parachute out of the body of the rocket. The weather did not effect our rocket in a negative nor positive way. There seemed to be no user error or equipment malfunction.  

Conclusion

Our rocket could have looked a lot better. We could have decorated it or made it look sleeker. The design was fairly solid but the nose cone and fins could use work. They were not exactly all the same size and the cone was slightly crooked. A correction to these would make the rocket fly higher and straighter. I would change this but nothing else. 

Calculations

Height at the top of trajectory:

The height given by the teacher was 80m. I believe that 80m is a more accurate measurement because 111.9 does not account for air resistance. The rocket did not fly directly straight up so the crooked path flight would effect the height of the apogee. I believe that the true height would be a lot less than 111 because of this. 80m is pretty far from 111 but it seems more reasonable, especially in comparison to other groups. 

  

Initial velocity: