Airwheel Hoverboards Associated with Einstein’s Theory of General Relativity

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Abstract: Riding one board makes it look like you’re gliding over the surface, sort of like hovering. To a certain extent, riding an Airwheel two wheel self-balancing electric scooter requires some physics. In this case, it’s associated with Einstein’s Theory of General Relativity. We can use it to explain an accelerating hoverboard.

People call them hoverboards, but they clearly don’t hover. If you haven’t seen one, it’s basically a Segway without the handle. Apparently, you may wonder how Einstein’s Theory relates with riding an electric scooter. First, don’t confuse this theory with the theory of special relativity. Special relativity is all about one simple thing: No matter how fast different people are moving, they all see the speed of light as the same constant value (3x 108 m/s).There are tons of cool things that come from special relativity—but we are going to talk about general relativity.

electric skateboard

The theory of general relativity says several things. But the main idea is that gravity is a result of curved space-time. If space-time is curved, then a light beam should be bent by a massive object—and yes, this actually happens. However, there is another effect of the theory of general relativity: you can’t tell the difference between acceleration and gravity. There you are standing still on your new hoverboard. Just standing there isn’t much fun. Since you want to go somewhere, you must accelerate. Here’s what happens when you accelerate on an electric scooter. You must rotate your ankles to turn on the electric motors in hoverboards, but you must also lean forward. If you don’t lean forward, you fall backward. Let’s consider a moment during this brief hovrboard acceleration.

The greater the acceleration of the hoverboard, the greater the lean angle is. Since the vector sum of these two gravitational forces must be along the direction of human body, there is a relation between the lean angle and the acceleration. You should be able to measure both the lean angle and the acceleration of the board to show this is true.

You can look at an accelerating airwheel self-balancing electric scooter from a stationary frame and there is only a vertical downward gravitational force or you can view it from the perspective of the person with an extra gravitational force. Either way, it’s still physics.