5. Discussion and Conclusion

5.1 Key findings

1. Tension of the string: The tension of the string is the has the potential energy. The more tension the string has, the more potential energy it has and the more energy will be released. This will also allow the vehicle to accelerate more.

2. Size of Wheels: By changing the size of the wheels the car can speed up or slow down. Wheels with a larger diameter have a greater travel distance per each turn as compared to wheels with a smaller diameter. With speed-trap racers smaller wheels will have a shorter travel distance per turn but will be much easier to accelerate and will require less pulling force to achieve the same acceleration as a larger wheel. Smaller drive wheels should be used on speed-trap racer in order to increase the acceleration and larger drive wheels should be used on long-distance travelers in order to cover more linear distance per rotation.

3. Mass of the Car: Since inertia is affected by mass, the car should have sufficient amount of mass. This is so that after the initial propel by the mousetrap, the car will stay in its state for a longer time, allowing the vehicle to travel for a longer distance.

4. Length of String and Length of Lever Arm: Longer lever arms will have less pulling force than shorter lever arm but longer lever arm will pull more string from the drive axle than shorter lever arm. Shorter lever arm with a short string have more pulling force and produce greater acceleration. Longer lever arm with a long string conserves energy better. The car moves slowly, but it travels farther because spring power is used more efficiently.

5. Type of base: The base should be strong and sturdy as the compressional force is great and the base must be able to withstand it.

6. Traction of the wheels: Friction is needed to propel the vehicle forward. The traction of the wheels should increase to produce greater acceleration, however, the traction of the wheels should not be too great that the car does not move forward.

5.2 Comparisons with other designs based on research

Diagram 1. Design by Scientific American Frontiers

Commentary: Conventional and steady. This design is ordinary, but it is stable when it travels.

Diagram 2. Design by William D. Jumper

Commentary: The materials used might not be suitable. Cardboard is not a good material as it is not durable and a little flexible. It is not streamlined.

Diagram 3. Design by Tom Schulz

Commentary: The designer has thought of the mass of the car. He/She has used minimum materials in an attempt to reduce the mass. With little force required to power the car, it is generally a good design.

Overall: The three designs are good and as compared to our design, the flaws in our design is that the mass of the vehicle is too much. This means that the force required to propel the car needed is much more.

5.3 Evaluation of engineering goals

Engineering Goals 
Develop a MouseTrap Car with the following specifications: 
(a) Uses only the MouseTrap provided as the only energy source 
(b) Has a maximum length of 30 cm, width of 10 cm, and a height of 10 cm 
(c) Can travel a minimum distance of 5 meters carrying an egg (the egg will be provided by the teacher) 
(d) All time-lines have to be adhered.
(a) The mousetrap was the sole energy. (Rating: 10/10) (b) The Mousetrap Vehicle has a length of 34.5cm, width of 13.8cm and a height of 12.2cm. 
(Rating: 8/10) (c) The car can travel a distance of up to 10m. (Rating: 10/10) (d) All timelines were adhered indeed. (Rating: 10/10)

5.4 Areas for improvement
The wheels could have been replaced with straighter ones, reducing the parabolic movement that is caused by the car turning. The mousetrap could also have been moved further in front, giving more space behind for the extension to be extended in length, allowing the string to also be increased in length, resulting in a longer travel time with more force applied.

5.5 Practical Applications
1. To create eco-friendly racing cars. A powerful spring can be used to power a car for a short distance.

2. Racing cars. We can use a powerful spring to first start up the car before using the engines. Racing cars can add such a function into racing cars instead of using solely on engines.

3. Using the spring as a sole source of energy, instead of using the compressed spring to power the wheels, it can be used in planes or boats to power the propeller.

5.6 Areas for further study

1.Material Science

(To search for low-cost and more suitable materials)'

2.Mechanical Engineering

(To engineer higher quality mechanical components such as gears and levels)

3.Design Engineering

(To inspire better and more efficient car designs)

4.Engineering Mathematics

(To calculate the length, size energy needed, force needed, etc)

5.7 Bibliography

Jumper, W. D. (2012). Modeling the mousetrap car. Retrieved 26 March, 2014, from http://scitation.aip.org/content/aapt/journal/tpt/50/3/10.1119/1.3685107

Mouse trap car. (n.d.). Retrieved 26 March, 2014, from https://sites.google.com/a/littleblue.usu.edu/stem/topics/mouse-trap-car

Lowen, C., Panico, S., & Jones, A. E. (n.d.). Building a better mousetrap car. Retrieved 26 March, 2014, from http://www.pbs.org/saf/1208/teaching/teaching.htm

Schultz, T. (2010). Mousetrap vehicle 2010 design. Retrieved from http://scioly.org/wiki/index.php/Mousetrap_Vehicle_2010_Design