Every thrill seeker gets their first taste of adrenaline from a roller coaster. I’ve never met someone who loves adrenaline but not roller coasters. And we’ve all seen the videos on Facebook of people freaking out on rides and passing out. But how fast does a roller coaster really need to go to make you pass out? Not a lot of people realize that it’s not actually about the speed, but rather the acceleration, and therefore the force exerted on your body.
Think about airplanes. They fly at a smooth 900 km/h at cruising altitude, and planes aren’t full of unconscious people — that would be dangerous. They start accelerating slowly, gaining more and more speed, until they reach their ideal velocity. So technically, if you had an excessively long roller coaster track, and a ridiculous amount of energy to power it, you could travel at almost the speed of light while remaining conscious.
Anyway, we still want to know when we are going to pass out. Obviously roller coaster designers have also done this math, or else their creations would be crazy health hazards. The way we’re going to calculate this is with “g”s. A g is acceleration resulting from gravity on Earth. If you drop any amount of weight from basically any height, it will have an acceleration downwards of about 10 m/s2, which is equal to one g. Most people can withstand five g’s of force. For reference, five g’s of force is enough to accelerate you up to highway speeds in just under a second.
On a roller coaster, the place you are going to feel the most force pushing on your body is at the bottom of a drop. Now of course, we can’t have our roller coaster turn at 90 degrees, or crash into the ground. That would cause other “problems” in addition to passing out. What I’m getting at is that if the roller coaster starts with a vertical drop but ends with a large sloping curve, you’ll feel less force than a roller coaster that ends in a sharp curve up. Let’s say the track goes from a vertical drop to horizontal in five metres of track. Throwing in some air resistance, we really only need the coaster to reach speeds of 60 km/h to hit that five g number. It turns out with just 60 feet of vertical track we can cause some people to pass out.
Remember, you can build roller coasters much taller than this, but to keep people happy and conscious, roller coaster designers don’t make the bottoms of the big drops nearly as sharp as we did here.
With all this said and done, if you really want to watch a friend pass out on a roller coaster, make sure they eat lots, drink little, and keep a low heart rate. Then, track down a roller coaster that is both tall and has the sharpest turn you can find. You just baked yourself a great viral video! This last part is a joke. Please do not attempt to make yourself — or other people — unconscious, because it is pretty bad for your health.
