Revision as of 17:06, 9 October 2025

Skateboard

Title text: I understand it's hard to do more than 300 feet on these 90-second rush jobs, but with a smaller ramp I'm worried the gee forces will be too high for me to do any tricks.

Explanation

This is one of 52 incomplete explanations:
This page was created by an extremely expedited half pipe. Don't remove this notice too soon. If you can fix this issue, edit the page!

In this comic, Cueball appears to have gone skydiving. In mid-fall, he opens what he thought was his parachute, only to discover the bag in fact contains skateboarding gear. This may be a reference to an incident where a skydiver switched his skydiving equipment for his camera equipment backpack and perished. Cueball blames himself for the error, pointing out that having something that is not a parachute in a bag that looks a lot like a parachute bag is practically inviting disaster.

After a beat panel, Cueball (still in mid-fall) takes out his phone and makes a call to a company responsible for skateparks, hoping to place an order for a half-pipe. Half-pipes are skating ramps consisting of a semi-circular surface that forms 180 degrees of an arc, allowing skaters to ascend vertically to perform tricks and then descend onto the same ramp. It seems Cueball's intention is to have a very large half-pipe transported to (or constructed at) his landing zone, then use his skateboard to land on the ramp. From there, he could either transfer his downward momentum into much more survivable horizontal momentum, or continue into the opposing ramp to transfer into upward momentum, which would be counteracted by gravity and produce a more meaningful fall.

Obviously, this idea is absurd; half-pipes are very large structures, and it would be difficult to move such a structure any meaningful distance in the time it would take Cueball to hit the ground, and still more time to build one in situ. Furthermore, it would have to be built or positioned to align closely with Cueball's line of descent, and ascertaining this would significantly delay the operation. The title text plays this for laughs, suggesting that the skatepark representative takes issue only with the size of the ramp that Cueball is requesting (600 feet), with the implication that a smaller half-pipe (300 feet) would be perfectly within their capabilities. Cueball tries to convince the rep to accept his original request due to his falling speed; making a high-speed turn inflicts significantly more g-force (unusually rendered as 'gee' in the comic) on the turner the tighter the turn is and the faster the turner is going, and humans have a tendency to black out under extreme g-force. While Cueball is confident in his ability to endure the g-force of a 600-foot halfpipe turn, he has less confidence regarding a much tighter 300-foot halfpipe - and, of course, because he is falling without a parachute, he does not have the option of slowing down in order to make the tighter turn more manageable.

Terminal velocity for a human falling in a prone orientation is about 55 m/s (123 mph). A ramp with a radius of 600 ft, or 180 m, would produce a centripetal acceleration of v²/r = 17 m/s². With 1 g (the acceleration of gravity at Earth's surface) being about 10 m/s², that's 1.7 g. A 300 ft radius ramp would generate about 3.5 g. In both cases, the acceleration vector (pointed radially) will add to the Earth's gravitational acceleration vector (pointed down), and be at a maximum at the bottom of the ramp. Assuming no change in velocity while skating on the ramp, that would be a max of 2.7 g on the 600 ft ramp and 4.5 g on the 300 ft ramp. The duration of the acceleration would be πr/v, about 34 s on the larger ramp and 17 s on the smaller ramp. Humans will generally black out under prolonged exposure to 4-5 g acting downward, as the forces pull blood away from the brain, so the difference between the 300 ft and 600 ft ramps could be the difference between tragedy and skating immortality. However, if Cueball were to land lying flat on the board, the g-forces would be survivable - humans can withstand sustained transverse accelerations of up to 11 g. The opportunities for tricks are more limited in that position, though.^{[citation needed]}

The human record for a controlled skateboard descent on an extremely tall ramp was set on 25 September 2025, about two weeks before this comic appeared, by Brazilian professional skateboarder Sandro Dias, who completed a controlled 70-meter skating descent on a skateboard ramp built to match the curved contour of an office building in Porto Alegre, Brazil, with a shape somewhat similar to a quarter-pipe. Dias started from rest, on a platform attached to the skate ramp, rather than first jumping out of an airplane and reaching terminal velocity, but he was able to maintain control throughout the extremely steep and high descent, reaching speeds of over 100 km/h without falling. Cueball is in a much more challenging position in various ways. Dias's feat actually confirms the conceptual plausibility of a 300-foot halfpipe, although he is currently the only person in the world ever to have safely descended such a large ramp, and the ramp built for his challenge was constructed on the side of an existing building over the course of an entire month, not in a matter of seconds.

Transcript

This is one of 27 incomplete transcripts:
Don't remove this notice too soon. If you can fix this issue, edit the page!

[Cueball falling in the sky facing, his back down, him facing upwards. He has a backpack on his back and a skateboard in his hand. Clouds are seen in the background.]

Cueball: I guess this is on me. I should really keep my skateboarding gear and my parachutes in different-looking bags.

[Cueball looking at his skateboard, still falling, now facing downwards]

[Cueball dialing on his phone, almost completely upside down]

BEEP BEEP

[Cueball talking on his phone, back facing upwards, similar to the first panel]

Cueball: Hello, Pro Skate Parks LLC? I'd like an extremely expedited order for a 600-foot halfpipe.

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Maybe Randall took inspiration for this comic from the recent Red Bull stunt with Brazilian skater Sandro Dias, who dropped from the side of a building from a height of 70 meters (that's little over 229 ft) on 25 September 2025. 2804:214:4102:575A:D862:C9B6:9505:D740 01:25, 9 October 2025 (UTC)vinnycordeiro

@vinnycordeiro, I thought of that too. [1] He was able to start in momentary free fall and make a controlled skating descent down the curve of the building (on a smooth skating ramp that had been built to exactly follow the building contour, not directly on the building's normal external surface). Although doing more than twice that height and starting at terminal velocity instead of rest would be extra-impressive. Still, Sandro Dias's achievement shows that a champion skateboarder can keep control of a skateboard with staggeringly large amounts of kinetic energy! Schoen (talk) 03:14, 9 October 2025 (UTC)

Perhaps the “wrong parachute pack” thing is just a common trope, but I was immediately reminded of the example in the Henry Stickmin Collection, where Henry survives the initial fall without a parachute just fine, but is immediately killed by the contents of the backpack falling out and onto his head. KelOfTheStars! (talk) 01:55, 9 October 2025 (UTC)

Parachute packs are secured with shoulder AND leg straps, so it's indeed very difficult to mistake them for ordinary backpacks. 194.119.24.136 08:39, 9 October 2025 (UTC)

Oh my gosh, how did I not notice that!? I am OBSESSED with THSC. RadiantRainwing (talk) 15:32, 9 October 2025 (UTC)

me when i realize that all my fandoms are dead (thsc, xkcd, alan becker.) 2.50.0.22 (talk) 05:23, 12 November 2025 (please sign your comments with ~~~~)

Wait, so "gee forces" isn't some kind of weird obscure pun? - 24.177.125.170 08:51, 9 October 2025 (UTC)

I wondered that too, but couldn't find any connection, other than that there is a TeamGee that makes electric skateboards, but it doesn't seem to be particularly notable (or even well thought of). 82.13.184.33 09:41, 9 October 2025 (UTC)

Has anyone done the math to see if the duration of the free fall would realistically be around 90 seconds as in the alt text? I want to believe Randall has, but the only way to know is to double-check... 81.1.2.155 09:06, 9 October 2025 (UTC)

OK this is me again, I just found an online calculator and for an 80-kg object, 90s corresponds to a fall of 5000 m, which is apparently a reasonable skydiving altitude. Of course he doesn't call just as he jumps so take 10 more seconds, that's 6000m. 81.1.2.155 09:13, 9 October 2025 (UTC)

But he would only realize his mistake at the moment of opening his parachute, which is typically around 1000-1200 m, leaving only 20-25 seconds before impact. 194.119.24.133 11:10, 9 October 2025 (UTC)

Terminal velocity in a flat orientation is something like 200 km/hr, or 55 m/s. The 600 ft halfpipe presumably describes the radius, so that's 180 m. Then, acceleration in a circular path is a = v^2/r, so making that turn would be 55^2 / 180 = 17 m/s^2. With 1 g = 10 m/s^2, that's under 2 g. A 300 ft, or 90 m ramp, would be about 3.5 g. Add 1 g when you're at the bottom of the ramp and your rotational acceleration is aligned with gravity, so 4.5 g on a 300 ft ramp. That is indeed at the 4-5 g's where sustained exposure will cause blackout. Note, it will take about 17 s to travel around a 90 m ramp. If Cueball can manage to land lying flat on the board, humans are much more tolerant of transverse g forces, up to 11 g's for 3 minutes, per https://www.goflightmedicine.com/post/pulling-gs-the-effects-of-g-forces-on-the-human-body But that would also probably prevent doing tricks.163.116.146.119 14:27, 9 October 2025 (UTC)

I think it's a reference to the new skate. game that's in early access because you commonly do insane stuff off building or while skydiving in the game. DetmerL (talk) 14:37, 9 October 2025 (UTC)

"the difference between the 300 ft and 600 ft ramps could be the difference between tragedy and skating immortality" Whoever wrote this deserves an award. Fephisto (talk) 15:10, 9 October 2025 (UTC)

Engineering

Skateboard

Assuming a landing speed of about 55 m/s (terminal velocity for a human falling in a spread-eagle position), and 52 mm diameter wheels, the wheels would spin at about 20000 rpm. Whilst that's well within the range for high quality wheels, the rotational acceleration on the wheels would be stressful; Cueball would need to land closer to upright to account for this initial resistance.

Kurahaupo (talk) 06:07, 16 October 2025 (UTC)

Add comment

@@ Line 16: / Line 16: @@
 After a {{tvtropes|BeatPanel|beat panel}}, Cueball (still in mid-fall) takes out his phone and makes a call to a company responsible for {{w|skatepark}}s, hoping to place an order for a {{w|half-pipe}}. Half-pipes are skating ramps consisting of a semi-circular surface that forms 180 degrees of an arc, allowing skaters to ascend vertically to perform tricks and then descend onto the same ramp. It seems Cueball's intention is to have a very large half-pipe transported to (or constructed at) his landing zone, then use his skateboard to land on the ramp. From there, he could either transfer his downward momentum into much more survivable horizontal momentum, or continue into the opposing ramp to transfer into upward momentum, which would be counteracted by gravity and produce a more meaningful fall.
-Obviously, this idea is absurd; half-pipes are very large structures, and it would be difficult to move such a structure ''any'' meaningful distance in the time it would take Cueball to hit the ground, and still more to build one ''in situ''. Furthermore, it would have to be built or positioned to align closely with Cueball's line of descent, and ascertaining this would significantly delay the operation. The title text plays this for laughs, suggesting that the skatepark representative only takes issue with the ''size'' of the ramp that Cueball is requesting (600 feet), with the implication that a smaller half-pipe (300 feet) would be perfectly within their capabilities. Cueball tries to convince the rep to accept his original request due to his falling speed; making a high-speed turn inflicts significantly more {{w|g-force}}s (unusually rendered as 'gees' in the comic) on the turner the tighter the turn is and the faster the turner is going, and humans have a tendency to black out under extreme g-force. While Cueball is confident in his ability to endure the g-force of a 600-foot halfpipe turn, he has less confidence regarding a much tighter 300-foot halfpipe - and, of course, because he is falling without a parachute, he does not have the option of slowing down in order to make the tighter turn more manageable.
+Obviously, this idea is absurd; half-pipes are very large structures, and it would be difficult to move such a structure ''any'' meaningful distance in the time it would take Cueball to hit the ground, and still more time to build one ''in situ''. Furthermore, it would have to be built or positioned to align closely with Cueball's line of descent, and ascertaining this would significantly delay the operation. The title text plays this for laughs, suggesting that the skatepark representative takes issue only with the ''size'' of the ramp that Cueball is requesting (600 feet), with the implication that a smaller half-pipe (300 feet) would be perfectly within their capabilities. Cueball tries to convince the rep to accept his original request due to his falling speed; making a high-speed turn inflicts significantly more {{w|g-force}} (unusually rendered as 'gee' in the comic) on the turner the tighter the turn is and the faster the turner is going, and humans have a tendency to black out under extreme g-force. While Cueball is confident in his ability to endure the g-force of a 600-foot halfpipe turn, he has less confidence regarding a much tighter 300-foot halfpipe - and, of course, because he is falling without a parachute, he does not have the option of slowing down in order to make the tighter turn more manageable.
-Terminal velocity for a human falling in a prone orientation is about 55 m/s. A ramp with a 600 ft radius, or 180 m, would produce a centripetal acceleration of v^2/r = 17 m/s^2. With 1 g (the acceleration of gravity at Earth's surface) about 10 m/s^2, that's 1.7 g. A 300 ft radius ramp would generate about 3.5 g. In both cases, the acceleration vector (pointed radially) will add to the Earth's gravitational acceleration vector (pointed down), and be a maximum at the bottom or the ramp. Assuming no change in velocity while skating on the ramp, that would be a max of 2.7 g on the 600 ft ramp, and 4.5 g on the 300 ft ramp. The duration of the acceleration would be πr/v, about 34 s on the larger ramp, and 17 s on the smaller ramp. Humans will generally black out under prolonged exposure to 4-5 g acting downward, as the forces pull blood away from the brain, so the difference between the 300 ft and 600 ft ramps could be the difference between tragedy and skating immortality. However, if Cueball were to land lying flat on the board, the g-forces would be survivable - [https://www.goflightmedicine.com/post/pulling-gs-the-effects-of-g-forces-on-the-human-body humans can withstand] sustained transverse accelerations of up to 11 g. The opportunities for tricks are more limited in that position, though.
+Terminal velocity for a human falling in a prone orientation is about 55 m/s (123 mph). A ramp with a radius of 600 ft, or 180 m, would produce a centripetal acceleration of ''v''<sup>2</sup>/''r'' = 17 m/s<sup>2</sup>. With 1 ''g'' (the acceleration of gravity at Earth's surface) being about 10 m/s<sup>2</sup>, that's 1.7 ''g''. A 300 ft radius ramp would generate about 3.5 ''g''. In both cases, the acceleration vector (pointed radially) will add to the Earth's gravitational acceleration vector (pointed down), and be at a maximum at the bottom of the ramp. Assuming no change in velocity while skating on the ramp, that would be a max of 2.7 ''g'' on the 600 ft ramp and 4.5 ''g'' on the 300 ft ramp. The duration of the acceleration would be π''r''/''v'', about 34 s on the larger ramp and 17 s on the smaller ramp. Humans will generally black out under prolonged exposure to 4-5 ''g'' acting downward, as the forces pull blood away from the brain, so the difference between the 300 ft and 600 ft ramps could be the difference between tragedy and skating immortality. However, if Cueball were to land lying flat on the board, the g-forces would be survivable - [https://www.goflightmedicine.com/post/pulling-gs-the-effects-of-g-forces-on-the-human-body humans can withstand] sustained transverse accelerations of up to 11 ''g''. The opportunities for tricks are more limited in that position, though.{{cn}}
-The human record for a controlled skateboard descent on an extremely tall ramp [https://www.redbull.com/int-en/sandro-dias-ultimate-skate-ramp was set in September 2025] by Brazilian professional skateboarder Sandro Dias, who completed a controlled 70-meter skating descent on a skateboard ramp built to match the curved contour of {{w|Centro Administrativo Fernando Ferrari|an office building in Porto Alegre}}, Brazil, with a shape somewhat similar to a quarter-pipe. Dias started from rest, on a platform attached to the skate ramp, rather than first jumping out of an airplane and reaching terminal velocity, but he was able to maintain control throughout the extremely steep and high descent, reaching speeds of over 100 km/h without falling. Cueball is in a much more challenging position in various ways. Dias' feat actually confirms the conceptual plausibility of a 300-foot halfpipe, although he is currently the only person in the world ever to have safely descended such a large ramp, and the ramp built for his challenge was constructed on the side of an existing building over the course of an entire month, not in a matter of seconds.
+The human record for a controlled skateboard descent on an extremely tall ramp [https://www.redbull.com/int-en/sandro-dias-ultimate-skate-ramp was set on 25 September 2025], about two weeks before this comic appeared, by Brazilian professional skateboarder {{w|Sandro Dias}}, who completed a controlled 70-meter skating descent on a skateboard ramp built to match the curved contour of {{w|Centro Administrativo Fernando Ferrari|an office building in Porto Alegre}}, Brazil, with a shape somewhat similar to a quarter-pipe. Dias started from rest, on a platform attached to the skate ramp, rather than first jumping out of an airplane and reaching terminal velocity, but he was able to maintain control throughout the extremely steep and high descent, reaching speeds of over 100 km/h without falling. Cueball is in a much more challenging position in various ways. Dias's feat actually confirms the conceptual plausibility of a 300-foot halfpipe, although he is currently the only person in the world ever to have safely descended such a large ramp, and the ramp built for his challenge was constructed on the side of an existing building over the course of an entire month, not in a matter of seconds.
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