We were brought around the Fabrication Lab and briefed about how to operate the relevant machinery there.
Then we proceeded to work on our design, fine-tuning it so that the process of cutting the materials to form the shape would be easier. We decided that one we would form a 'T' at the hitting end of the car, ensuring that the bottom of the vertical piece doesn't touch the bottom of the ground, but at the same time has enough clearance over the wheels. Obviously this will cause a moment when the ruler hits the can, causing the car to possibly be unaligned with it. For now we plan to either weigh the other end of the horizontal plane or supporting the base of the cart with weights (like how some construction trucks do when lifting heavy objects).
We also made a bolt and nut design to swing the ruler.