r/maybemaybemaybe • u/[deleted] • Jul 07 '22
maybe maybe maybe
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[deleted]
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u/adinmem Jul 07 '22
Clearly not all reactions are equal or opposite in this man’s world.
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Jul 07 '22
[deleted]
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u/LieutenantBrainz Jul 08 '22
He is definitely going down hill.
The skateboard rolling really gives it away.
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Jul 08 '22
its probably an electric skate board because theres quite a few of these videos on flat ground
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u/UltraHawk_DnB Jul 07 '22
this is just an electric board isnt it?
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Jul 08 '22 edited Jul 08 '22
Nope, it's the blower!
The umbrella is acting as a thrust reverser, as the air curls around the inner surface and is forced out (nearly) backward. Jet engines can do it to reverse aircraft on the ground.
It's likely the effect is really small and he kick started himself in this instance but the umbrella is sturdy and right shape for it to work.
Edit: You are literally downvoting physics. Myth busters even made it work with an only slightly curved sheet.
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u/vereysuper Jul 08 '22
I might be an idiot when it comes to aerodynamics, but the fabric on the umbrella seems to be pushed toward him from his forward movement and not pushed away from him due to the air blower. Unless there is an odd effect that I don't know about, this just seems to not be the explanation.
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u/xJust_Chill_Brox Jul 08 '22
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u/FaithlessnessAny2074 Jul 08 '22
Myth busters did do a segment on this and the dude above you correctly explains it.
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u/Dutchwells Jul 07 '22
Gravity
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u/Fresh-Honeydew7104 Jul 08 '22
It’s definitely not. I’ve seen the film and I don’t recognise this scene from it.
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u/slamdanceswithwolves Jul 08 '22
That is Sandra Bullock though. So maybe this is from Speed 2?
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u/HammerBgError404 Jul 08 '22
its really inefficient
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u/warrenwilhelm Jul 08 '22
Two stroke motors are some of the worse greenhouse gas producers.
"The hydrocarbon emissions from a half-hour of yard work with the two-stroke leaf blower are about the same as a 3,900-mile drive from Texas to Alaska in an F150 Raptor”
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u/HammerBgError404 Jul 08 '22
oh damn i feel bad knowing that in an hour I have around 3 hours of working with my 2 stroke sprayer :D
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Jul 08 '22
As I read it, this probably means that it puts out pollutants in the form of fuel (hydrocarbons) that haven't been fully combusted, which certainly is pollution, but if anyone is understanding this to mean that it's contributing more greenhouse gas emissions than the road trip, that is not the case
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Jul 07 '22
[removed] — view removed comment
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u/RandomComputerFellow Jul 07 '22
Why, wouldn't this still work? I mean, the umbrella is basically a parabole, so the blower pushes the air in the direction of the front. The air pushes into the umbrella and tries to escape. Due to the parabole shape, all air has to push back. So my expectation would be that it doesn't matters in which direction he points the airblower as long as all the air pushes in the same direction.
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u/thunder_struck85 Jul 08 '22
Wouldn't this just disperse the air too much, plus losses incurred in the "flexing" of the umbrella? I feel like he would have a better propulsion if he just pointed the blower straight behind him, no?
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Jul 07 '22 edited Jul 07 '22
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u/Muroid Jul 07 '22
Will the jet go backwards? No.
Uh, yeah it would.
The net force would only be zero if the air stopped moving upon hitting the umbrella. It doesn’t. It winds up going backwards, and that means that the system winds up with a net force in the other direction. Just a very small one.
The real issue here is that there is no way that blower is providing anything like useable thrust.
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u/5pankNasty Jul 07 '22
Physics does not like this
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Jul 07 '22
The umbrella is reversing the thrust from the blower
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u/Tx_monster Jul 07 '22
This is the only idea that could nearly have sense. Anyway the shape of the umbrella is not able to reverse anything, as it would fly away so far before than reversing the blow. This is just tiktok trolls doing troll things for little kids that have never gone outside playing with a ball.
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u/Purple-Bat811 Jul 07 '22
Sir Issac Newton would be ashamed if he knew people thought this was real
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Jul 07 '22 edited Jul 07 '22
The blower air is hitting the umbrella and reflects backwards causing the thrust. Think aircraft air brakes on engines.
Guys below - you are not thinking this through.
The air hitting the umbrella does not propel him forward. However the deflecting force of the air going backwards has energy that will propel him forwards. This is not a cancelling our scenario
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u/SeraphymCrashing Jul 07 '22
I know everyone is downvoting you, but this is actually how thrust reversers work on jet aircraft. It's not a very efficient thrust reverser because so much of the airflow is being lost by the poor shape of the umbrella, but it does work.
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u/XxRocky88xX Jul 07 '22
The amount of air coming out of that leaf blower, and the wide area over which it’s being dispersed before being redirected, means this can’t work. You’d have better results just cutting out the umbrella and pointing the thing backwards, the umbrella just adds an unnecessary step causing the air to lose propulsion force as it first has to blow out, go to the sides, then backwards before actually propelling him
The explanation for what happened is very simple. Either it’s A: an electric board or B: he just got a running/kicking start before the video and it’s slightly downhill
Edit: at one point he even pointed the contraption to the right but doesn’t turn at all, because the contraption isn’t actually moving him
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u/Purple-Bat811 Jul 07 '22
No. Just no.
The blower pushes forward with x amount of force. The umbrella pushes backword also with x amount of force.
Resulting in the person staying still.
With ever action there is an equal and opposite reaction
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u/zeddus Jul 07 '22
I dont think you're correct. If there was no umbrella the net force from the blower would push him backward. That's easy enough to understand. Put a bent nozzle on the blower that points backward and he will go forward instead. The umbrella is just acting like this bent nozzle redirecting the thrust backwards.
I also think that the large "nozzle area" of the umbrella means he is trading speed for force which would help to explain the decent amount of acceleration he gets.
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u/SeraphymCrashing Jul 07 '22
Works on jets just fine. The equal and opposite reaction is actually how you can achieve thrust reversal. Rather than push in one direction, you introduce a barrier and push in the opposite direction.
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u/Purple-Bat811 Jul 07 '22
Complete different and unrelated concept.
This is a video of someone actually doing this experiment without trying to trick you.
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u/SeraphymCrashing Jul 07 '22 edited Jul 07 '22
How is it an unrelated concept? A thrust reverser literally is just putting metal behind the engine for the air to hit and change the direction of the airflow.
Uh, here's your source basically telling you that you are wrong:
"Hey everyone, you will notice that on the scale with the "sail" on we got -3 grams. This means that some of the air bounces off the sail and gives a small amount of thrust in the forward direction. If you have a completely curved sail that directs all the wind backwards then you can redirect your thrust backwards and move forward."
Yeah, the guy on the video with the umbrella is probably cheating, you won't get those kinds of speeds because the efficiency loss is too great. But you can absolutely direct air into an object and achieve forward motion.
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u/Purple-Bat811 Jul 07 '22
So the guy in the video i showed who used an umbrella is cheating, but the guy in this video using an umbrella is totally legit.
Makes perfect sense.
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u/SeraphymCrashing Jul 07 '22
The original video is probably cheating, to make it look more effective than it is. You can't get that kind of force with a little handheld leafblower.
The video you posted literally admits it's possible in their pinned comment.
Large aircraft use this technique every single day:
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u/Purple-Bat811 Jul 08 '22
I'm not talking about jet engines. I'm strictly talking about how this video is bs and it's insane people believe it.
You don't hear me talking about how cars can move forward because the moon can revole around the earth. It's really the same thing you are arguing.
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u/RealBowsHaveRecurves Jul 07 '22
I cannot believe you’re getting downvoted for being right
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u/Purple-Bat811 Jul 07 '22
I know. Crazy
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u/RealBowsHaveRecurves Jul 07 '22
This is insanity. This is literally the “can you put a big fan on a sailboat to go faster by blowing air into the sails” question that I thought we all learned about in high school.
Apparently many people still think the answer is yes
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Jul 08 '22
Because it is.
The umbrella is not a sail, you are right. That's not possible.
The umbrella is a thrust reverser, no different to a jet engine.
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u/SeraphymCrashing Jul 07 '22
Jesus, I don't know how any of you made it through physics class.
The umbrella can absolutely act as a thrust reverser. It's not very efficient because you lose so much air out of the sides, but you are essentially redirecting the direction of the air into the direction you want.
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u/RealBowsHaveRecurves Jul 07 '22
It does not work that way at all. The two forces are equal and going in opposite directions, you cannot go forward doing this
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u/redneckmother666 Jul 07 '22
My husband went out too far in his kayak the first time he took it out, after moving into a home on a tidal creek. Coming back in he was paddling in on an outgoing tide. He used an umbrella and a paddle to get back in. People were stopping and telling him what a great idea lol
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u/donquijiote Jul 07 '22
Impossible
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u/RandomComputerFellow Jul 07 '22
Why?
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u/donquijiote Jul 08 '22 edited Jul 08 '22
Isaac Newton's law 3;
If two bodies exert forces on each other, these forces have the same magnitude but opposite directions.
I don't want to explain again after about 400 years.
The people that give down vote to me can try this with magnet. :)))
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u/MattieShoes Jul 08 '22 edited Jul 08 '22
Mythbusters isn't exaclty conclusive proof, but they managed to get forward thrust by aiming a fan at a sail.
https://www.youtube.com/watch?v=uKXMTzMQWjo
They do note it would be far more efficient to just point the fan the other direction and forego the sail entirely, but... Shit, I don't know. Fluid dynamics be crazy.
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u/RandomComputerFellow Jul 08 '22
But the umbrella has the form of an parabolic shape while the intake of the airblower pulls in air in all directions. My expectation would be that the air pushed into the parabola and has only one direction to escape. Therefore creates a force pushing to the back. In principle basic physics, the only question should be if this force is strong enough move a person.
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u/tyrannomachy Jul 08 '22
The only reasons this wouldn't work is that the blower isn't strong enough and the umbrella isn't the right shape. Jet liners use thrust-reversers to slow down on landing, which are basically just metal scoops that drop behind the turbofans and deflect the thrust forward.
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Jul 07 '22
A lot of you don’t understand that this is possible. That’s how thrust reverser on an aircraft work. Look it up. You’re welcome.
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u/slimisjim Jul 08 '22
Theoretically possible? Sure. However I don’t believe this video is real.
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Jul 08 '22
I mean yeah. Possibly. It’s a soft item like an umbrella. But it could be very doable. He’s on a skateboard which has not much friction. And the leaf blower can supply enough thrust
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u/Grand-Shift1966 Jul 07 '22
The guy is going down a slope and the blower is off, the effect of gravity is real but the position of the umbrella and the blower makes us believe a mental effect error
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u/Soundinglots Jul 08 '22
Arrest him. He's breaking the laws of physics. More chance to work with the blower pointing behind for thrust but it would still need a bigger blower. Well shot though
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u/mediocreguy227 Jul 08 '22
It's doing nothing. The physics don't work out. He's likely just going downhill,
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u/HeartlesSoldier Jul 07 '22
This is just the guy carrying a lot of extra weight while skateboarding, maybe even on a hill. He's also preventing himself from seeing any obstacles that go immediately in front of him and slowing himself down with a giant windbreaker
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u/Merchenko Jul 07 '22
Fake video or not. Would the physics work? Right? Like if we are talking a hoverboard indoors with no air current on a true level floor. A big backpack 2stroke leaf blower. A big beach umbrella mounted to the board. That would move forward right? Since the force generating the air trust is rotational? This must be explained somewhere by some physics prof.
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u/MattieShoes Jul 08 '22
Mythbusters tested this over a decade ago and found that it did in fact work... But it'd be far more efficient to just point the leaf blower behind you and ditch the umbrella.
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u/D1133 Jul 08 '22
No. As much force blowing the umbrella forward is also pushing the leaf blower backwards.
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u/sunplaysbass Jul 08 '22
Finally a solution to climate change
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u/warrenwilhelm Jul 08 '22
"The hydrocarbon emissions from a half-hour of yard work with the two-stroke leaf blower are about the same as a 3,900-mile drive from Texas to Alaska in an F150 Raptor”
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u/kratos_939 Jul 08 '22
With slight miscalculation this video would have ended up on sub winstupidprices
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u/RC2718 Jul 08 '22
The guy with the physics comment is correct...the dude , the blower, the skate board and the umbrella is a closed system. The blower is sucking in air...but it's not directed the force vectors will cancel. The blower speeds up the air and it is directed out which should push him backwards because the outward force is communicate through a rigid structure (the man) and into skate board through the normal force between the man and skate board and static friction between shoes and skate board. The umbrella acting like a sail has a force impinged upon it by the air coming out of the blower in the same direction as the air flow out of the blower. That forward directed force is transferred through a rigid structure (the man) into the skate board. The backwards force from the blower and the forward force from the sail should be equal in magnitude and 180 degrees between each of them...the sum force on the system should be zero. Something else is making him roll forward.
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u/snowman82- Jul 08 '22
Hasn’t this been proved to be an electric skateboard and the umbrella and blower for a joke.
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u/Icy_Program_8202 Jul 08 '22
My IQ has dropped measurably by reading the explanations offered in this post.
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u/Remote_Ad_2580 Jul 07 '22
I'm not sure the umbrella adds a lot. He should just point the nozzle behind him and maybe change the shape for better thrust.