At what force would a human being need to fart in order to achieve lift off?

19 replies, posted

Assuming that a 180 pound individual is sitting on a leather sofa in a prepared bracing position, how strong would the emission from his asshole need to be in order for him to propel his body atleast one foot in the air?
What would be the quantity of force required to propel himself five feet in the air?
How much force would he require in order to make his head hit the ceiling if the ceiling is 9 feet away in relation to the ground?

And would his colon rupture before that could happen?

Let's for now presume that none of his internal or external organs would be damaged from the strength of the eruption.

Well, I'm not physicist, but I'll try to remember what I can from high school science class.
Gravity's downward force is calculated by multiplying the acxeleration due to gravity by the object's mass.
Gravity's acceleration is usually 9.8m/s.
Let's just convert pounds (weight) into kilograms (mass), because iirc they're different somehow.
180 lbs = 81.65 kilograms, roughly.
Google tells me that 1kg of mass at 1m/s would be 1N (newton) of force.
9.8 * 81.65kg = 800.17N
So a 180 pound person has 800.17 Newtons of downward force opposing their liftoff.
I suppose that you'd need at least 800.17 Newtons of upward force to get just a moment of a weightless feeling.
But I have no clue how to proceed from here, to calculate how many newtons of force to be moving upward while gravity continues to pull down. This is where my high school science knowledge ends unfortunately.

Amazing! I wonder what the equivalent of something of 800 neutons of force would be in real life or what it could be compared to.

At a very basic level, as long as the force in newtons counteracts the person's gravity in newtons, they'd lift off. It depends how big the person is, of course. To really know though, you'd have to think about the weight of whatever is being ejected. Whatever gas is exhausted would have to be under extreme pressure.
My advice is to buy a few meals from Chipotle and you can run some tests yourself.

I wonder if Chipotle could be recommended to cooperate with Nasa to utilize these tests in order to develop personal space propulsion devices.

this reads like a fart fetish thread disguised as some weird high school physics question

threads that make you go hmmm

I think it would be like the force that a trampoline would bounce you upward, but not quite enough to make your feet leave the surface.

No sexual arousal intended, just pure science.

I was curious to know what that amount of Newtons would look like in context, so I wondered:
How many Newtons of force would be involved in getting hit by a semi truck on the freeway? The biggest easily-available force, I'd imagine.
Semi trucks are allowed a maximum of 80000 lbs, or 36287.39 kg.
Rural freeways have a upper speed limit of 70 mph, or 112.65rkm/h.
So let's line that up and do some basic conversation until we get our newtons.
N = 36287.39 kg * 112.654km/h
N = 36287.39 kg * 112654 m/h
N = 36287.39 kg * 31.29 m/s
Getting hit by a semi truck carrying the maximum weight going the rural freeway speed limit would hit you with 1,135,432.43N, or over a million newtons of force.
Boy howdy
It feels like a question I'd ask when researching physically-plausible magic for a novel.
Or a stoner question
Either way, it's all in good fun

Would it be not unreasonable to assume that 1500 newtons would be enough to achieve some quantity of liftoff given that 800 is enough for the trampoline bump example? or Would it be closer to like 2500?

The physics of a fart
Someone else estimated that farts weigh 1.3 grams per liter. Our average fart contained 1/28th of a liter of gas, and that would work out to 0.0464 grams. That's the same ballpark as my estimate just above.
Yet another person (no bibliography will be appended to this answer) estimated that the emission speed of a fart is 3 meters per second. If that is true, then the momentum imparted by a fart is 0.00012 kg m / sec, and the kinetic energy would be 0.00018 Joules.
i'm too tired right now to figure out how many farts you'd need to do using these measurements to achieve lift off.

If I was going make a wild guess, I would think you'd need 800N plus another 800N for every second you want to move directly upward.
My problem is that I dont know how to calculate how quickly you would move upward, or how much time gravity has to push you down 800N every second.

This is a little off topic, but contains many useful equations and estimates for the force needed to lift a body from the ground
https://www.youtube.com/watch?v=uvg7rPJEKJc&t

Well the thing is that there are different possibilities of propulsion based on the type of emission.
It could be like a very smooth and relatively slow upwards ascent or it could be a immediate cannon like fire of the whole gas more comparable to being propelled by an explosion.

but what would it smell like haha

Probably like a geiser at Yellowstone. The more important question is how much ear protection one would need for the sound of it.

Y'all need jesus
https://files.facepunch.com/forum/upload/111032/67a1fa48-c42e-43a2-9470-b3ee73d3878f/fuMpB5O.png

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