Group: Sonoma Booth, Faith Fox

Drawings of Design:

Tinker Cad 40 tooth Gear Design:

Circuit Design:

Reasoning for Designs:

Car design:

• Why we are using Cardboard– We decided to use cardboard as the base material so the car is light and it is easy to construct.
• Why we are attaching the motor to the back wheels– We found that in theory, rear wheel drive is faster than front wheel drive. When the car is accelerating, all the weight shifts to the back end of the car where the driving wheels are, allowing more traction. (https://yousuckatracing.com/2021/11/08/rwd-vs-fwd-part-1/#:~:text=There%20are%20a%20lot%20of,line%2C%20RWD%20wins%20every%20time.)
• Why we chose to include a rear wing– The rear wing reduces the low pressure zone behind the car, which means less turbulence is created and drag force is reduced. This creates downforce so that the vehicle has more traction and stability at higher speeds. (https://aia.springeropen.com/articles/10.1186/s42774-020-00054-7#:~:text=The%20low-pressure%20zone%20behind,2).&text=The%20wing%20is%20another%20essential,is%20different%20in%20its%20functioning.)
• Why our Gear ratio is 4:1– A 4:1 Gear ratio will increase the torque of the car. Torque is the cars ability to do work, which is one of the subjects we learn in Physics 11. The more torque car has, the more power the engine can produce, which allows the car to accelerate from rest quicker. (https://www.kia.com/dm/discover-kia/ask/what-is-torque-in-a car.html#:~:text=Simply%20put%2C%20torque%20is%20a,vehicle%20is%20beginning%20to%20start.https://rozum.com/how-to-calculate-gear-ratio/#:~:text=If%20the%20gear%20ratio%20is,speed%20but%20boost%20the%20torque.)
• Why we chose to have the axels in straws– This will allow the axels to spin freely within the straws so the car can accelerate.

Circuit Design:

• Why we chose to use an H-Bride circuit– An H-Bridge circuit allows a car to move forwards and backwards. Switches are used to open and close the circuits, which allows the current flow to in opposite directions. This, in turn, will change the direction the gears and wheels spin. (https://www.modularcircuits.com/blog/articles/h-bridge-secrets/h-bridges-the-basics/)

Materials List:

• Cardboard
• Hot glue gun
• 1 driver gear (10 teeth)
• 1 driven gear (40 teeth) à gear ratio = 4:1
• DC motor
• Batteries and battery pack
• 4 Wheels (Makerspace)
• 4 Axle (wooden stick) x2
• Plastic straw for axle to go in
• Paint or Colured Paper for design (McQueen)