Have you ever seen a car driving so fast – either in a movie or real life – that as it drives around the corner it tilts up on two wheels? That is so totally not a safe way to drive a car, but now some people are driving like that on purpose. It’s called “sidewalk skiing,” and it’s all the rage in the country of Saudi Arabia. As you can see in this crazy video, the cars lurch to one side then the other to get themselves up on two wheels, then all the riders in the car move around to balance their weight so the car stays balanced, while the driver steers to keep the car on its side. They seem to be going straight enough and fast enough to drive on a regular street, so maybe this isn’t a bad way to drive after all. However, you need other people in the car to balance it, so this will only work for carpool time.
Wee ones: If a 4-wheeled car starts skiing with just 2 wheels on the ground, how many wheels are up in the air?
Little kids: If 6 cars go out to sidewalk-ski, how many wheels are driving on the ground? Bonus: How many wheels do they all have in total?
Big kids: If you need to drive 62 miles an hour to tilt the car onto two wheels, and you’re going only 47 miles an hour, how much faster do you need to drive to do the stunt? Bonus: If you have 4 riders who each weigh 190 pounds, how many pounds of weight do you have handy to balance the car?
The sky’s the limit: The center of mass for a bunch of things on a straight line is the point where if you multiply each thing’s weight times its distance from the center, the total for all things on one side adds up to the total for all the things on the other side. If you have 3 riders in the car, A B and C, who weigh 140 pounds, 150 pounds and 200 pounds, plus their 40-pound pet dog, and they can each sit either 1 foot or 2 feet from the center of mass, who has to sit on which side and how far away to balance each other out?
Wee ones: 2 wheels in the air.
Little kids: 12 wheels. Bonus: 24 wheels.
Big kids: 15 miles an hour faster. Bonus: 760 pounds.
The sky’s the limit: There are a few ways to balance it out. It balances if you put B, the 150-pounder, 2 feet to the left of center, the dog 1 foot to the left of center, and the other two riders 1 foot to the right of center (presumably one sitting in the other’s lap). The 150 weight times 2-foot distance gives you 300, and the dog 1 foot from center adds 40, yielding 340. If you seat the 140-pounder A and the 200-pounder C 1 foot to the right of center, they add 140 and 200, which also totals to 340. Another way is if the 200-pounder C and the 40-pound dog sit on to the left of center, with C 2 feet away and the dog 1 foot away. On the other side, the 150-pounder B would be 2 feet from center and the 140-pounder A would be 1 foot. Then both sides total 440.