PT2.1 Engineering Goals

2.1 Engineering Goals & Brainstorming

Part 1:
We have chosen Weight, Size, Appearance, Time to produce and Safety as the design criterions.

Part 2:
Design 1:
The mousetrap car is made up of 4 components: the back wheels, front wheels, chassis and mousetrap extension. The back wheels consists of CDs that are taped along their edges to add friction and bottle caps on the inner side to prevent it from moving to much to the left or right. These parts are joined together with a satay stick. The front wheels consists just of a set of wheels and a satay stick to join them. The chassis is made of two parallel wooden sticks along the length of the mousetrap. Metal hoops are screwed into the ends of the wooden stick to allow the axles to be connected to the chassis. and the mousetrap is taped on top of the wooden sticks. The mousetrap has an extension made of wooden sticks that consists of two beams parallel to the sides of the mousetrap lever and two connecting beams, one at the edge for use and one halfway for support. The stick at the edge has a string tied to it and the string will be later on rolled into the back wheel axles.

Design 2
A vinyl record is connected to each side of the satay stick (the axle). The vinyl record is surrounded by rubber tape to provide more friction. The mousetrap is left hanging in the middle of axle with a string tied to the end of the lever which will be rolled around the axle.

Design 3
A CD surrounded by rubber tape to provide frcition is connected to each side of a satay stick. This forms the front and back axle. The front and back axles are pierced through a two small pieces of wood which are then glued to the base of the mousetrap. A piece of string is then tied to the lever of the mousetrap which will be rolled around the back axle.

A. Rules and Regulations

Teams will design and build their own vehicles which must be solely powered by the standard issue mousetrap. Competition rules are as follows:

1. The standard issue mousetrap must be mounted onto the vehicle chassis.
2. The spring on the mousetrap may not be cut, bent, over-wound, heat-treated or altered in any manner.
3. No additional source of elastic potential energy should be incorporated into the engine/drivetrain mechanism
4. Additional input of energy of any form to the vehicle is forbidden.
5. Participants may supply their own materials and are encouraged to use recycled, re-purposed materials; kits are prohibited.
6. Distance traveled will be measured in a straight line, with reference to the front axle of vehicle from start point to the point where the front axle stops or leaves the designated testing area.
7. Vehicles must have either 3 or 4 wheels.
8. Engineering modifications such as gearing, use of lubricants, bushings and bearings are permitted.
9. The final assessment will consist of a maximum of 3 trial runs out of which the run with the best score will be recorded; the vehicle cannot be modified further once it has started on the first trial run and all 3 runs must be conducted within the same day.
Exception: Minor adjustments that are approved by the teacher assessor may be allowed on a case-by-case basis; all adjustments approved and carried out must be documented by the respective teams.

B. Final Assessment

Scoring in the final assessment will be based on (i) maximum distance travelled in a straight line and (ii) vehicle run time (from start to stop of motion).
Calculation of the total score will follow the following mathematical formula:

Total Score = 70 - 10p + 2d - 2(t - 1)

Base score 100 pts
Number of rule violations p (min: 0 pts)
Each 0.5 meters travelled (up to 8 metres) d (max: 15 pts)
Run time in seconds (at least 1 second) t (min: 1 pt)

Example: Team A's mousetrap car travelled a straight line distance of 4.0 m in 2.0 s, and they have 1 rule violation. Their total score = 70 - (10 x 1) + 2 x (4.0 / 0.5) - 2(2.0 - 1) = 74

To get the maximum score of 100, a team needs to get a straight distance of at least 7.5 m in a time of 1.0 s and have zero rule violation.

If the team does not have a working mousetrap car on the day of final assessment (e.g. the vehicle fails to move on launch or the vehicle is not completed or missing), there will be a penalty of - 50 (i.e. the team will score 70 - 50 = 20).

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