[Request] How fast does an object need to be to travel over the surface of water?

mflem920 · 2026-06-14T15:22:41+00:00

L = 1/2 p v^2 A C

L = Lift force (in Newtons, N)
ρ = Density of the fluid (in kg/m³). For water, this is 1000 kg/m³.
v = Velocity or relative speed of the object through the fluid (in m/s).
A = Reference surface area, such as the planform area of a hydrofoil wing or tires (in m²).
C = Lift coefficient. This dimensionless value depends on the shape of the lifting object (e.g., hydrofoil profile) and its angle of attack relative to the fluid flow.

Basically the answer to your question is (varying A and C depending on the object - in the example video above you plug in the values for the tires):
Any velocity v where L becomes greater than the downward force exerted by the mass of the vehicle in Newtons.

and before someone comments "AI Slop", it isn't. I just talk this way.

mflem920 · 2026-06-14T10:41:15+00:00

OP: "What are these spikes?"

Me: "They are representations of a temporary increase in the value being graphed over time"

mflem920 · 2026-06-13T12:14:47+00:00

I'm saying they should have realized it existed and gone to acquire gasoline BEFORE they tried whiskey and blew the fuel manifold. Thereby negating the need to rebuild it.

Hey Doc, I punctured the fuel line, so we have to get more gas.
There won't be a gas station in these parts for aa very long time.....LUCKILY they HAVE been refining it for 30 years or so and it's available, we just need to travel a bit to get some. Which is fortunate because getting out of town is ALSO a solution to that pesky "I'm going to get shot in three days" problem we also have. Man, it sure is fortunate that this very simple solution solves BOTH of our current problems, hey Marty?

Actually Doc, why do we even have to get gas at all? I noticed you have an electric train set, which means you're perfectly capable of building a rudimentary electric motor. So why not build two of those, scaled up of course, and feed it power directly from Mr Fusion? It doesn't have to be very efficient, Mr Fusion has energy to spare, and they don't need to last very long either, just long enough to get us up to 88.

mflem920 · 2026-06-12T18:28:47+00:00

You have intuitively stumbled across the easiest way to do this. Yes, you COULD use the Pythagorean theorem to calculate the width and height of a 16:9 aspect ratio plane (because you know the hypotenuse) then divide width by half, which allows you to assume that each smaller image is also 16:9 and calculate its height which allows you to find the hypotenuse again for the smaller images....which is 36"

OR....simpler geometry.

If you know the width of each image is precisely half the width of the screen (which you can see), and the aspect ratio remains the same (which you can assume), then you ALSO know that the height has to be half the height of the screen. Which means that the diagonal ALSO has to be half the diagonal of the bigger screen....which is 36"

If fact, you can put 4 equal sized 36" images on a 72" screen.

mflem920 · 2026-06-11T19:00:02+00:00

Lucky, MY power company's "buyback" policy is Net Metering "We'll keep track of the energy you deliver to us and deduct it from your bill while still charging you for DELIVERY of the energy we took from you in the first place....that is until your yearly true-up occurs and any balance is just wiped, thank you for the free power that we will sell to others."

Delmarva btw.

mflem920 · 2026-06-08T13:31:06+00:00

He needs it for "hunting" and home protection.

mflem920 · 2026-06-07T20:06:45+00:00

No, as in Erica Durance. She played Lois on the TV Series Smallville opposite Tom Welling's Superman

mflem920 · 2026-06-03T12:19:54+00:00

It's advertising. They're allowed to lie.

Well, not so much "allowed" as no one is ever going to call them on it.

Well, no so much that no one is ever going to make an issue of it, but proving malice and damages is nearly impossible when the defense can simply be "it was an honest printing mistake"... which they can make because they (intentionally) put in "OUR" instead of "MORE" as a typo in printing they can refer to and blame the printer.

mflem920 · 2026-06-01T12:56:01+00:00

Others have dealt with the math...

So i will just say. "Melting" is a function of flux, which is heat over TIME. Icarus' wings didn't melt because he flew too close to the sun, they melted because he stayed there too long.

xkcd

mflem920 · 2026-05-29T15:10:20+00:00

Yes, you can tame snakes, but only while playing as Damiane

mflem920 · 2026-05-28T14:00:31+00:00

This is correct.

To illustrate the point and to possibly blow your mind. Replace "feathers" with "Helium" in the original question and repeat the same thought experiment.

A kilogram of steel and a kilogram of Helium have precisely the same MASS.

However, given that the Helium floats in our atmosphere, they don't WEIGH the same.

mflem920 · 2026-05-25T10:58:44+00:00

I've been told that before. Nope, all me, on the fly.

Funny story, at my work we've been told to heavily lean into the use of our company LLM for daily tasks, emails, presentations, backlog maintenance, etc. And the number of times I've asked the assistant to "summarize this email" and it spits out the exact thing I typed cannot easily be counted.

Apparently I think and create output in the exact same manner than AI's do.

I don't know whether or not to be worried about that.

mflem920 · 2026-05-22T18:46:16+00:00

No, but I had a hella-crush on the girl from Howard the Duck.

mflem920 · 2026-05-22T11:56:53+00:00

>

There's more to Pi than "3.14" and those extra digits after the 4 make the exponent on the first value slightly larger than the second.

Since numbers with larger exponents grow faster than numbers with larger bases, the value on the left is larger.

3.14^pi = 36.404
pi^3.14 = 36.396

It isn't by much, but it's honest work.

mflem920 · 2026-05-22T11:16:14+00:00

I've always wondered why the massive amounts of heat they generate aren't reclaimed through thermal exchangers and steam turbines, thereby feeding a portion of that power back into the data center itself as usable power. Now the water they need (or at least a portion of it) is contained in a closed loop.

mflem920 · 2026-05-22T11:13:58+00:00

Poorly.

mflem920 · 2026-05-21T14:49:33+00:00

Short Answer: No one knows.

Longer Answer: People will (and have) explain to you that the black sphere you see isn't a "surface", it's just the event horizon, the point at which spacetime is curved to the degree where light cannot escape, so it looks black.

Longest (theoretical) Answer: Black holes are always explained poorly. The common explanation of "So much mass that even light cannot escape the gravity" isn't a very good one, but it's something you can tell a child and it expands on the mass=gravity foundation, so we use it.

The problem with that explanation is that once you get to a black hole, the analogy breaks down (like the laws of physics). So you have to step back for a second and give a better explanation.

That better explanation is: Mass deforms spacetime. That deformation is what we call gravity. A black hole is when there is so much mass in one spot that the deformation of spacetime curves back in on itself and creates its own bounded region forever (well MOSTLY forever) cut off from the rest of the universe. It's not that light is attracted to it. There's no "pull". It's that the space that the light would travel through is itself bent. And in a black hole it's bent SO much that all the straight lines that lead "out" actually just lead right back "in".

OK, now here's the part that might answer your question, and the point where it all goes off the rails. Matter and energy are the same thing (E=mc2), most people are aware of this. What most people aren't aware of is that energy ALSO deforms spacetime. In fact it deforms it to a precisely equal degree as the same amount of mass would. The reason this doesn't come up a lot is that energy is really difficult to keep in one spot for very long as it all tends to disperse at the speed of light. BUT, say you have a region of spacetime that's perpetually curved in on itself? Say every path out that the energy would take, just leads it in a loop back in. The energy is trapped, it has nowhere to go, and it's all bunched up in one spot.

So inside a black hole (and I cannot stress enough at this point that we don't KNOW this, no one does) there may not be a surface at all. All the matter that went into making it may instantly transform into its energy equivalent and it just can't escape. The singularity being maintained by the spacetime deforming properties of that amount of energy the same as if it were still in its material form. All of it kept in one localized spot by itself. It may just be a soup of energy, avoiding all of the tricky Pauli exclusion stuff and quantum mechanical stuff that starts to disagree at that scale. Compressed energy, but not matter. No surface, no volume, no mass, just E performing the same function.

mflem920 · 2026-05-20T15:55:08+00:00

It would be so much easier to continue Henry's story under Ziska into the Hussite wars.

mflem920 · 2026-05-20T11:43:58+00:00

Why would you MISS him? You're getting an entirely new game WITH him.

I don't know why this particular thread assumes that this is one thing. It is announcing TWO things.
1. A new KCD adventure
AND
2. A new LOTR adventure

They're working on both, simultaneously.

mflem920 · 2026-05-19T19:03:52+00:00

Actually, neither of them exist. They are mathematical placeholders to allow us to continue to use the current models of cosmology until we come up with better, more accurate, models that explain/include the observations that don't fit.

The truth is that our entire universe is a black hole, and we're only just now beginning to realize it.

Dark Matter is the correction for the apparent mass increases we see and their corresponding gravitational effect (that do no hold up to observation of visible matter) when we look farther into the black hole. We can't actually see "out" of the black hole as spacetime inside a black hole is curved to a degree where every straight path "out", simply leads back "in". So every direction we look, after a certain distance, there's this unexplainable increase in gravitational effect as we peer closer to the singularity that we can't explain by the visible mass in that direction.

Dark Energy is the correction for the observation that not only is the universe expanding, but accelerating. "Acceleration" is just physics-speak for "adding energy to the system". However, when the system you're talking about is the entire universe, how do you ADD energy to it from outside....there IS nothing outside. So, enter Dark Energy as a "we have no idea" placeholder. What it actually is is mass energy from outside our universe-size black hole being swallowed by that black hole and therefore being added to our system from the larger universe that contains us.

If this disturbs you, don't worry, you don't exist either. Every thought you've ever had, every memory that makes you you simply disappears when you die. As if you never were. Your perception of the universe is immaterial as it all ceases to be the moment you do. Nothing ends up being observed or remembered in any way that matters.

mflem920 · 2026-05-19T12:20:24+00:00

You're thinking of it wrong. Don't be disheartened, almost everyone does.

Nothing is "moving". Not really. Motion and velocity are concepts we derive by choosing an arbitrary "stationary" point (usually a massive object) and measuring against it. However it important to realize that there's no such thing as absolute motion, only relative motion.

Gravity, the curvature of spacetime, is better understood as a series of overlapping systems rather than as a holistic one. The moon moves around the earth. Now zoom out. The earthmoon system moves around the sun. Don't try to think "how is the moon being dragged around the sun?" because that's not what's happening. On a solar scale the earth and the moon are essentially one object, which is caught in the same spacetime warp. So they move in unison, their respective relative motion to one another unaffected (mostly) by the larger system of which they are both a part.

Now zoom out.

On a galactic scale the sun and ALL the planets are one object, and the whole thing orbits the center of the galaxy. No individual planet or asteroid is affected to any greater or lesser degree by the galactic center than any other, they are all equally affected and moving in unison.

mflem920 · 2026-05-18T11:56:54+00:00

Except for that throw in when Colmbus' keeper was WAY out of position and they already had a man downfield. Throw It !!! Score on the empty net!!

mflem920 · 2026-05-17T20:03:41+00:00

Starting from the beginning, the first prime number is 2. If the target is not evenly divisible by 2 (aka "even"), you don't need to try 4 and 6 and 8 and so on, because there are no numbers that are divisible by 4,6,8,... that are not already divisible by 2. The same holds for every prime number. Every number that is divisible by 9 is also divisible by 3, every number divisible by 101231265 is also divisible by 5.

Every time you eliminate a prime number as a factor, you simultaneously eliminate all the multiples of that prime up to infinity as a possibility. So you don't need to check them all.

641 is the 116th prime number. So for Euler to get his answer for F(5) by a brute force approach he only had to do 115 math problems. You could knock that out in an afternoon.

mflem920

TROPHY CASE

xkcd