Skullgrid@lemmy.world
on 18 Sep 17:28
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I mean, yes and no.
~~en.wikipedia.org/wiki/Terminal_velocity#Physics ~~
Heavier objects have a higher “max speed” that they can fall at, compared to lighter objects. The acceleration to that relative speed is constant though. More or less.
IE : While a bowling ball and a ping pong ball might start falling at the same initial rate, eventually the bowling ball will fall faster.
EDIT : Ignore me for now, I need to do more digging.
rockerface@lemmy.cafe
on 18 Sep 17:37
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Yeah, it’s not like they just blindly accepted what he said. They held up a feather or a leaf or a sheet of paper and a lead weight and dropped them both at the same time and the lead weight hit the ground while the leaf was still fluttering in the wind.
That’s not because of weight though. That’s just one thing being affected more by air resistance. In a vacuum, there would be no difference. In fact, they did just that during the Apollo 15 mission on the moon using a feather and a hammer:
Without the m as the browser will decide for itself if it needs the mobile version.
NoneOfUrBusiness@fedia.io
on 18 Sep 18:00
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The acceleration to that relative speed is constant though. More or less.
It's not. Air resistance will affect lighter objects more due to Newton's second law and the square-cube law, resulting in heavier objects accelerating faster than light ones. Only at the initial instant, where there is no air resistance due to the speed being 0, will two objects of different weight be subject to the same downward acceleration.
LustyArgonianMana@lemmy.world
on 19 Sep 00:55
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Collatz_problem@hexbear.net
on 18 Sep 17:47
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Due to air resistance, heavy objects do tend to fall slightly faster in atmosphere.
LifeInMultipleChoice@lemmy.dbzer0.com
on 18 Sep 18:28
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Take a balloon, fill it with air and drop it from a plane next to say a brick. The balloon may not hit the ground for awhile, especially if it gets caught in some air streams
When accounting for air resistance, heavy objects do fall faster than light ones. They couldn't test in a vacuum back then, they only knew how things work here in Earth's atmosphere.
frezik@lemmy.blahaj.zone
on 18 Sep 18:31
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A similar size chunk of iron and coal would have done the experiment just fine. Any two objects of the same shape and size but significantly different densities.
If two objects have the same size and shape, the force applied by air resistance will be the same. However, if two objects have different mass, that same force will result in different acceleration.
StellarExtract@lemmy.zip
on 18 Sep 19:54
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While that is true, two properly selected objects (such as the ones mentioned above) can reduce the effect of air resistance to levels negligible to human perception, demonstrating that heavier objects do not intrinsically fall faster.
The difference is the different buoyancy of the balls in air. That’s negligible.
ColeSloth@discuss.tchncs.de
on 18 Sep 21:12
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Not at all. Our air is made up of physical objects (molecules of oxygen and nitrogen, mostly). Things with more mass, more quickly knock those out of the way.
For a demonstration you can see and more easily wrap your head around, take something just barely heavier than water, and a similarly sized heavy rock and drop them in a pool. You’ll see how much quicker the rock gets to the bottom, because it displaces the water so much faster. Our atmosphere is the exact same.
It seems maybe you’re actually misunderstanding. As I mentioned above, both you and the other commenter are certainly correct that the surrounding atmosphere (water in your case) exerts force on the objects as they fall, with varying effects depending on object density. However, if you take two objects that have vastly more density than the water (let’s say a big tungsten rod and another tungsten rod that has a hollow core), they will drop at approximately the same rate in the water even if their density vs each other varies. The greater the difference of their density versus the density of the medium, the less the effect of the medium. Is there still technically an effect? Sure, but that effect is negligible from a human perceptual perspective.
ColeSloth@discuss.tchncs.de
on 19 Sep 18:22
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I understand what you’re saying (call it like a 10" 100 pound tungsten ball vs a 5" 50 pound tungsten ball) but your reasoning and logic of being essentially the same are just silly and the math that would dictate when each would land in atmosphere would still line up perfectly (which would be that the heaviest one will hit first). even if it were a 10,000 pound ball and a 5,000 pound ball.
The acceleration will be 1G minus drag. The Earth is sufficiently larger than anything one would drop off a tower so the weight of the dropped thing doesn’t matter at all
How does your model of the universe explain the hammer and feather dropped on the moon by Apollo 15’s David Scott landed at the same time?
Ed. There is an effect of buoyancy that will make denser things fall faster. It becomes noticeable in distances where the dropped items reach terminal velocity or on more dense media where buoyancy is more significant.
In air over short distances buoyancy is negligible, in vacuum there is none
mnemonicmonkeys@sh.itjust.works
on 18 Sep 20:29
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The Earth is sufficiently larger than anything one would drop off a tower that the weight of the dropped thing doesn’t matter at all
F=ma.
Two items of the same shape will have the same amount of air resistance. If they have significantly different masses, the two object experience commensurately different accelerations (or reduction in acceleration), even if the force is the same.
If you take a balloon full of tetrahexofluroride (a gas 6x the density of air) and a chunk of iron the exact same size and shape and throw them off a building, I guarantee the iron chunk will hit first.
How does your model of the universe explain the hammer and feather dropped on the moon by Apollo 15’s David Scott landed at the same time?
It’s called a vacuum, which is famous for not having air resistance. Y’know, the thing we’re talking about?
To perform the experiment properly on Earth where there is air resistance, you need to pick a shape and range of masses that minimize the effect of air resistance
If F is the same but m is different, what happens to a?
Rivalarrival@lemmy.today
on 19 Sep 00:53
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Buoyancy is functionally irrelevant here. Buoyancy in air effectively subtracts 1.3kg per cubic meter of each substance: The mass of the volume of air displaced by the object.
The part you are not understanding: Drag applies the same force to both objects. Gravity applies the same acceleration to each object.
Read their claim again: they are specifically describing the effect of air resistance. Their claim is perfectly consistent with the lunar feather/hammer experiment.
Their problem was that they weren’t able to say why, and no one replying to me was able to do more than say they’re right, I’m wrong. See my edit. I added a correction after looking up drag equations for myself and finding that buoyancy was a factor
Two items of the same shape will have the same amount of air resistance. If they have significantly different masses, the two object experience commensurately different accelerations (or reduction in acceleration), even if the force is the same.
The “same force” they are talking about is drag. The two objects are the same size and shape. At the same velocity, drag affects them both equally, applying an equal, upward force against both objects.
Gravity (in a vacuum) accelerates both objects equally. But they have differing masses. F=MA. F/M = A. A is equal for both objects. Because acceleration is equal, the “force” on each object is not: the force must be proportional to its mass: The high mass object must be experiencing high force; the low-mass object must be experiencing low force.
Subtract the “same force” of drag from the downward force on both objects, and the net force on each object is no longer proportional to the mass of each object. Consequently, the high-mass object accelerates in atmosphere faster than the low-mass object. The high-mass object has a higher terminal velocity; the low-mass object has a lower terminal velocity.
For the purposes of this experiment, buoyancy is functionally irrelevant. The effect of buoyancy is to subtract a fixed mass from each object: A mass equivalent to the mass of air displaced by the object. Effectively, buoyancy slightly reduces the density of both objects. The actual difference in the densities of the two objects is far greater than the slight change due to buoyancy in air, so buoyancy is not a significant factor.
You’ll get hit by what you’re told to get hit by and you’ll like it.
mnemonicmonkeys@sh.itjust.works
on 18 Sep 20:33
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Nope, denser objects fall faster than less dense ones (through the air).
Technically it’s objects with a higher mass-to-drag ratio, but most of the time it’s close enough
misteloct@lemmy.dbzer0.com
on 19 Sep 02:58
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Not really true, it’s definitely possible for a less dense object to fall faster than a denser one. A drop of water will fall faster than a parachute made of nylon, which will fast much faster than a glider plane made of metal.
Clocks existed then though. The oldest clocktower in Europe that still exists was built over 100 years before Galileo was born, and time measurement existed longer than that. You can measure time fairly accurately with water clocks which had been known for thousands of years before Galileo. Not having “modern” pendulum clocks yet doesn’t mean that they didn’t have any way to measure time. Even without water clocks you can get decently reliable measurements of time with rhythmic chants (think how today we might say "one Mississippi, two Mississippi, etc.). Early alchemical recipes often include time measurements in chanting a specific prayer or passage a certain number of times during a specific step. Sure you’re not going to get milisecond level accuracy this way but you don’t really need that for a lot of things. Hero of Alexandria built mechanical automata 1500 years before Galileo using pulleys and weights as timers. Time measurement not only existed before pendulum clocks, it was pretty decent.
With same gravity constance everything fall down at the same speed, but only in a vacuum. In an atmosphere there count the air resistance of an object, even if they are made of the same material and weight, an iron sphere of 1 kg fall faster than a iron sheet of 1 kg.
multifariace@lemmy.world
on 18 Sep 21:21
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That’s why Gallileo’s balls were so special.
KurtVonnegut@mander.xyz
on 18 Sep 22:58
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With two metal balls, one solid and one hollow, you could rule out the role of resistance?
I assume you mean keeping the outer diameter the same and making one ball lighter than the other. That’s clever, it would eliminate aerodynamism as a factor.
However wouldn’t results still vary, since hollowing out the metal ball increases its buoyancy ? (Archimedes’ principle).
heatofignition@lemmy.world
on 19 Sep 02:07
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They would have the same coefficient of drag, correct, but the air resistance would end up having more effect on the lighter mass of the hollow sphere, so it would be slightly slower to fall.
Archimedes principle here is accounted for in the different weights. Everything that you can put on a scale is already being acted on by Archimedes principle in air.
Except if you could measure exactly the speed of objects falling in a vacuum, the heavier object would appear to fall faster due to the gravitational pull on the Earth. You’re forgetting the Earth falls toward the object too.
No, mass or weight of an object is irrelevant, in one of the jurney to the Moon, astronauts demostrate it with an hammer and a feather on the moon that both fellt at the same speed. It exist one gravity aceleration, on earth is 9,82 ms², which is the force of acceleration which experiment any object on Earth, the only difference which can slow it down is the resistant of air, this can be different in each object, but without atmosphere there is nothing which slow down the acceleration of the object, it’s irrelevant the material, weight, mass or form. Basic physic
The difference is far too small to measure at these scales, the Earth would be falling toward the more massive object faster than the less massive object. Therefore the more massive object hits first.
mnemonicmonkeys@sh.itjust.works
on 19 Sep 20:13
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Therefore the more massive object hits first.
Only technically. The effect you’re describing is so minute that it’s insignificant.
It’s like pointing out that the Great Pyramids of Giza are so massive that time moves 1 billionth slower for the surrounding objects. It’s neat that the effect is potentially measurable, but noone is going to be adjusting their clocks to account for it
Science is built on technicalities. In an exam, if a student considered the centre of m_1 as the centre of gravity instead of the weighed centre of m_1 and m_2 they would fail. This is no different
mnemonicmonkeys@sh.itjust.works
on 20 Sep 22:28
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Your analogy doesn’t hold up, because factors get ignored in physics discussion all the time. Whem was the last time you’ve see a question in a dynamics class that didn’t ignore air resistance for the sake of simplicity?
The effect you’re describing is orders of magnitude smaller than that. I doubt the change would even register in a double floating-point variable if you did the calculations in Matlab
heatofignition@lemmy.world
on 19 Sep 02:16
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R^2 is on the bottom. We don’t ignore the mass of one object because it’s insignificant, that would make the top of that equation 0 and the object wouldn’t fall at all.
That nifty gravitational law gives you the force of gravity on an object, not the acceleration. Force also equals mass times the resultant acceleration, right? So Fg1 = m1*A1 = G*M*m1/r^2 and Fg2 = m2*A2 = G*M*m2/r^2. m1 and m2 are present on both sides of those equations, respectively, so they cancel, and you get A1 = G*M/r^2 and A2 = G*M/r^2, which are identical. The mass of an object affects the force of gravity, but when you look at acceleration the mass terms cancel out.
Doing the math: 1,000,000,000 x 0.5 = 500,000,000 grams of water droplets in our cloud. That is about 500,000 kilograms or 1.1 million pounds (about 551 tons). But, that “heavy” cloud is floating over your head because the air below it is even heavier— the lesser density of the cloud allows it to float on the dryer and more-dense air.
Planes, helicopters- lots heavy stuff not falling faster than lighter ones
You can find exceptions, but on average, heavier objects will fall very slightly faster than light ones, because they excert their own gravity field onto Earth and therefore pull it towards themselves.
This requires a somewhat unintuitive definition of “falling”, in that both the object and Earth itself moves, but given that any object with mass excerts a gravitational field, there is not actually any other definition.
LustyArgonianMana@lemmy.world
on 20 Sep 15:25
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Wut? This does not turn off gravitational pull for objects other than Earth.
Or I’m misunderstanding what you’re trying to say, but yeah, no clue.
LustyArgonianMana@lemmy.world
on 20 Sep 16:21
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You didn’t read it, it is literally telling you you are wrong.
By experimenting with the acceleration of different materials, Galileo Galilei determined that gravitation is independent of the amount of mass being accelerated
“… in a uniform gravitational field all objects, regardless of their composition, fall with precisely the same acceleration.”
What is now called the “Einstein equivalence principle” states that the weak equivalence principle [above] holds
Tests of the weak equivalence principle are those that verify the equivalence of gravitational mass and inertial mass. An obvious test is dropping different objects and verifying that they land at the same time. Historically this was the first approach – though probably not by Galileo’s Leaning Tower of Pisa experiment[19]: 19–21 but instead earlier by Simon Stevin,[20] who dropped lead balls of different masses off the Delft churchtower and listened for the sound of them hitting a wooden plank.
Between 1589 and 1592,[1] the Italian scientist Galileo Galilei (then professor of mathematics at the University of Pisa) is said to have dropped “unequal weights of the same material” from the Leaning Tower of Pisa to demonstrate that their time of descent was independent of their mass
Newton measured the period of pendulums made with different materials as an alternative test giving the first precision measurements.[3] Loránd Eötvös’s approach in 1908 used a very sensitive torsion balance to give precision approaching 1 in a billion. Modern experiments have improved this by another factor of a million.
Experiments are still being performed at the University of Washington which have placed limits on the differential acceleration of objects towards the Earth, the Sun and towards dark matter in the Galactic Center.[45] Future satellite experiments[46] – Satellite Test of the Equivalence Principle[47] and Galileo Galilei – will test the weak equivalence principle in space, to much higher accuracy.[48]
With the first successful production of antimatter, in particular anti-hydrogen, a new approach to test the weak equivalence principle has been proposed. Experiments to compare the gravitational behavior of matter and antimatter are currently being developed.
Ah, I’m not saying there’s a different force being applied to feather vs. hammer. The meme above doesn’t mean that they “fall faster” in the sense that the hammer falls at a higher velocity. It’s rather colloquial usage of “faster” to mean “finishes sooner”. Because what does happen, is that the hammer collides sooner with Earth, since the hammer pulls the Earth towards itself ever-so-slightly stronger than the feather does.
I guess, for this to work, you cannot drop hammer and feather at the same time in the same place, since they would both pull Earth towards themselves with a combined force. You need to drop them one after another for the stronger pull of the hammer to have an effect.
But setting mass_1 as Earth’s mass and mass_2 as either the feather’s or hammer’s mass. A higher mass_2 ultimately leads to a higher force of attraction F.
LustyArgonianMana@lemmy.world
on 20 Sep 21:33
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So in that equation, let’s say mass 1 is earth. G and distance will be equal in both instances of dropping.
Rewrite equation:
Distance^2/ G*mass 1 = mass 2 /force
And
Distance^2/ G*mass 1 = mass 3 /force
Therefore,
Mass 2 /force = mass 3 /force
F = m*a
Mass 2 / mass 2*a = mass 3 / mass 3 * a
This cancels out to show that a = a, their acceleration is the same.
WizardofFrobozz@lemmy.ca
on 19 Sep 01:45
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I am most certainly not a science whiz but it’s so goddamn funny to see this whole comment section full of people just… explaning and correcting each other poorly with varying degrees of correctness. Just like 50 half-true and misremembered tidbits from everyone’s intro to high school physics class, blindly seeking targets in space. I promise you guys, there’s a very straight answer to this like two or three clicks away, written more clearly and succinctly than anyone here is managing to do.
fossilesque@mander.xyz
on 19 Sep 02:02
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Don’t tell them that. You’re contaminating my petri dish. ;)
I have noticed there is a bit of a more “anti intellectual” bent on Lemmy compared to Reddit. Like there is a lot of stupidity on reddit but usually someone comes in with actual knowledge. On Lemmy I just see people arguing in circles with each other with nobody ever actually looking anything up.
farngis_mcgiles@sh.itjust.works
on 19 Sep 13:35
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actually your wrong
burntbacon@discuss.tchncs.de
on 19 Sep 13:42
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You’re*
wrong right
FTFY
farngis_mcgiles@sh.itjust.works
on 20 Sep 20:23
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stop bullying me 😭
burntbacon@discuss.tchncs.de
on 23 Sep 03:50
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Stop
I can’t, you’re being intellectual on lemmy and we have an anti-intellectual bent here. I am compelled by the lemmy force to do this again.
swelter_spark@reddthat.com
on 19 Sep 14:42
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IMO, it’s okay to have casual conversations without being an expert or researching every post. Redditors’ habit of fact-checking everything is honestly tiring. Conversation has other purposes besides education. I think many people are looking more for human interaction than for correct facts.
Right but conversations about science where all parties are wrong and nobody is willing to actually look shit up are completely pointless. It’s the exact same problem that caused the situation in the OP in the first place.
Like there is a lot of stupidity on reddit but usually someone comes in with actual knowledge
Be careful with that, actually. Reddit mastered repeating an explanation or analogy they read on another thread or saw on YouTube, but being quite eloquent at explaining it. Problem is, if they misunderstood it to begin with, they’ll just as confidently repeat a broken version.
I didn’t notice it at first… then I started seeing explanations for things on my field and cringed at how wrong they were, and then I started noticing the pattern and the very repeated analogies on other areas too.
DreadPirateShawn@lemmy.blahaj.zone
on 19 Sep 02:11
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Rosencrantz: [holds up a feather and a wooden ball] Look at this. You would think this would fall faster than this.
[drops them. ball hits the ground first]
…and you would be absolutely right.
davidagain@lemmy.world
on 19 Sep 05:17
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To be fair to Archimedes, heavy objects do usually fall faster than light ones*, and to be fair to Newton, stuff coming towards you usually has a higher relative velocity than things going away from you.+
*You need your objects to be weigh a lot relative to their air resistance to notice otherwise.
+You need some pretty ambitious equipment to detect that electromagnetic radiation such as light does not follow this pattern.
If you like novels I highly recommend Galileo’s Dream by Kim Stanley Robinson. It has a moment where Galileo realizes you could “weigh” time, in his experiments with objects rolling down an inclined plane.
fullsquare@awful.systems
on 19 Sep 07:00
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Aristotle said so much dumb shit, like he said that women have less teeth and never bothered to check
Matriks404@lemmy.world
on 19 Sep 11:59
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What if a planet that is Earth-sized falls down on Earth from let’s say 5-10 meters though?
It would fall at 2g, because two Earth-sized masses attract each other in that case.
With smaller objects it’s just 1g, because the mass of, let’s say, a nice cup of tea is negligible compared to the mass of Earth.
A thing that size would have initial velocity to begin with,
But acceleration does not depend on mass, (which is kinda weird from an earthling’s perspective), which Einstein formalized in an amazingly powerful theory called General Relativity
threaded - newest
I mean, yes and no.~~en.wikipedia.org/wiki/Terminal_velocity#Physics ~~Heavier objects have a higher “max speed” that they can fall at, compared to lighter objects. The acceleration to that relative speed is constant though. More or less.IE : While a bowling ball and a ping pong ball might start falling at the same initial rate, eventually the bowling ball will fall faster.EDIT : Ignore me for now, I need to do more digging.
In a medium, which is an important distinction
Yeah, it’s not like they just blindly accepted what he said. They held up a feather or a leaf or a sheet of paper and a lead weight and dropped them both at the same time and the lead weight hit the ground while the leaf was still fluttering in the wind.
That’s not because of weight though. That’s just one thing being affected more by air resistance. In a vacuum, there would be no difference. In fact, they did just that during the Apollo 15 mission on the moon using a feather and a hammer:
…wikimedia.org/…/File:Apollo_15_feather_and_hamme…
Hey buddy! I came to post that video!
I know what is happening. I know why it is happening. My brain is still screaming at the feather to slow down.
…wikimedia.org/…/File:Apollo_15_feather_and_hamme…
Without the m as the browser will decide for itself if it needs the mobile version.
It's not. Air resistance will affect lighter objects more due to Newton's second law and the square-cube law, resulting in heavier objects accelerating faster than light ones. Only at the initial instant, where there is no air resistance due to the speed being 0, will two objects of different weight be subject to the same downward acceleration.
en.m.wikipedia.org/wiki/Equivalence_principle
I can’t tell if this is you chastising me or giving me a shovel to help me dig.
Lol I think it’s the research you were missing and I already had the link copied. Wasn’t being a jerk for once, just was giving you info
all good then, thank you :)
Without the m as the browser will decide for itself if it needs the mobile version.
<img alt="" src="https://lemmy.world/pictrs/image/f8fa3797-2a8b-4823-9962-26db011acd70.gif">
It’s how Arthur fell faster then Fenchurch. He was heavier.
Who?
Arthur Dent
The Sandwich Maker!
The trick was to throw yourself at the ground and miss
I always do this.
Except of course when I don’t.
Due to air resistance, heavy objects do tend to fall slightly faster in atmosphere.
Take a balloon, fill it with air and drop it from a plane next to say a brick. The balloon may not hit the ground for awhile, especially if it gets caught in some air streams
When accounting for air resistance, heavy objects do fall faster than light ones. They couldn't test in a vacuum back then, they only knew how things work here in Earth's atmosphere.
A similar size chunk of iron and coal would have done the experiment just fine. Any two objects of the same shape and size but significantly different densities.
If two objects have the same size and shape, the force applied by air resistance will be the same. However, if two objects have different mass, that same force will result in different acceleration.
While that is true, two properly selected objects (such as the ones mentioned above) can reduce the effect of air resistance to levels negligible to human perception, demonstrating that heavier objects do not intrinsically fall faster.
The difference is the different buoyancy of the balls in air. That’s negligible.
Not at all. Our air is made up of physical objects (molecules of oxygen and nitrogen, mostly). Things with more mass, more quickly knock those out of the way.
For a demonstration you can see and more easily wrap your head around, take something just barely heavier than water, and a similarly sized heavy rock and drop them in a pool. You’ll see how much quicker the rock gets to the bottom, because it displaces the water so much faster. Our atmosphere is the exact same.
It seems maybe you’re actually misunderstanding. As I mentioned above, both you and the other commenter are certainly correct that the surrounding atmosphere (water in your case) exerts force on the objects as they fall, with varying effects depending on object density. However, if you take two objects that have vastly more density than the water (let’s say a big tungsten rod and another tungsten rod that has a hollow core), they will drop at approximately the same rate in the water even if their density vs each other varies. The greater the difference of their density versus the density of the medium, the less the effect of the medium. Is there still technically an effect? Sure, but that effect is negligible from a human perceptual perspective.
I understand what you’re saying (call it like a 10" 100 pound tungsten ball vs a 5" 50 pound tungsten ball) but your reasoning and logic of being essentially the same are just silly and the math that would dictate when each would land in atmosphere would still line up perfectly (which would be that the heaviest one will hit first). even if it were a 10,000 pound ball and a 5,000 pound ball.
The acceleration will be 1G minus drag. The Earth is sufficiently larger than anything one would drop off a tower so the weight of the dropped thing doesn’t matter at all
How does your model of the universe explain the hammer and feather dropped on the moon by Apollo 15’s David Scott landed at the same time?
Ed. There is an effect of buoyancy that will make denser things fall faster. It becomes noticeable in distances where the dropped items reach terminal velocity or on more dense media where buoyancy is more significant.
In air over short distances buoyancy is negligible, in vacuum there is none
F=ma.
Two items of the same shape will have the same amount of air resistance. If they have significantly different masses, the two object experience commensurately different accelerations (or reduction in acceleration), even if the force is the same.
If you take a balloon full of tetrahexofluroride (a gas 6x the density of air) and a chunk of iron the exact same size and shape and throw them off a building, I guarantee the iron chunk will hit first.
It’s called a vacuum, which is famous for not having air resistance. Y’know, the thing we’re talking about?
To perform the experiment properly on Earth where there is air resistance, you need to pick a shape and range of masses that minimize the effect of air resistance
You are wrong. Falling in a medium is slowed by buoyancy and drag
F=ma has nothing to do with it
Motherfucker, do you seriously not understand that buoyancy and drag are forces?!?!
Sit yo’ Dunning-Kruger ass down
en.wikipedia.org/wiki/Dunning–Kruger_effect
Without the m as the browser will decide for itself if it needs the mobile version.
Valid crashout. 🤣
On Earth, this is the part that makes it so that objects do not fall at the same speed.
This is the type of experiment they could not do 2000 years ago.
That is incorrect. Drag affects both equally. The difference is caused by buoyancy, less dense objects feel more buoyancy
If F is the same but m is different, what happens to a?
Buoyancy is functionally irrelevant here. Buoyancy in air effectively subtracts 1.3kg per cubic meter of each substance: The mass of the volume of air displaced by the object.
The part you are not understanding: Drag applies the same force to both objects. Gravity applies the same acceleration to each object.
Thanks that does make sense
Drag doesn’t exist in a vacuum.
Read their claim again: they are specifically describing the effect of air resistance. Their claim is perfectly consistent with the lunar feather/hammer experiment.
Their problem was that they weren’t able to say why, and no one replying to me was able to do more than say they’re right, I’m wrong. See my edit. I added a correction after looking up drag equations for myself and finding that buoyancy was a factor
Also, thank you for replying civilly
They did. You didn’t understand what they said.
The “same force” they are talking about is drag. The two objects are the same size and shape. At the same velocity, drag affects them both equally, applying an equal, upward force against both objects.
Gravity (in a vacuum) accelerates both objects equally. But they have differing masses. F=MA. F/M = A. A is equal for both objects. Because acceleration is equal, the “force” on each object is not: the force must be proportional to its mass: The high mass object must be experiencing high force; the low-mass object must be experiencing low force.
Subtract the “same force” of drag from the downward force on both objects, and the net force on each object is no longer proportional to the mass of each object. Consequently, the high-mass object accelerates in atmosphere faster than the low-mass object. The high-mass object has a higher terminal velocity; the low-mass object has a lower terminal velocity.
For the purposes of this experiment, buoyancy is functionally irrelevant. The effect of buoyancy is to subtract a fixed mass from each object: A mass equivalent to the mass of air displaced by the object. Effectively, buoyancy slightly reduces the density of both objects. The actual difference in the densities of the two objects is far greater than the slight change due to buoyancy in air, so buoyancy is not a significant factor.
So change the shape, a long copper rod and clump of coal.
If you do that then they definitely won't fall the same.
And the iron would hit the ground much faster because it pushes air molecules out of the way quicker.
They could just drop an empty bs filled wine bottle.
Maybe fill it with mercury (but don’t drink it)
Nope, denser objects fall faster than less dense ones (through the air). Remember: A kilogram of feathers is just as heavy as a kilogram of lead.
I’ll still choose to be hit by the feathers.
You’ll get hit by what you’re told to get hit by and you’ll like it.
Technically it’s objects with a higher mass-to-drag ratio, but most of the time it’s close enough
Not really true, it’s definitely possible for a less dense object to fall faster than a denser one. A drop of water will fall faster than a parachute made of nylon, which will fast much faster than a glider plane made of metal.
They did figure out the earth was round and measure its size with sticks and shadows though, so that’s pretty cool.
make a vacuum without bamboo, and with roman/early-medieval tech 😤
What about bamboo
The thing that always gets me about the Renaissance is Galileo:
He did those experiments with things falling down? Measuring speed?
Yeah. Without a clock.
The theory for how to build those came later, based on what Galileo did.
Man, being a cop must have sucked before they invented time.
Officer: do you know how fast you were going?
Lord: No, do you?
Officer grumbles: you’re free to go.
Carriage pulls away
Officer ClocknTime: For now, for now.
Alright, I’m stealing this one for a Pathfinder session
Couldn’t even measure it in Mississippis because they hadn’t discovered it yet.
Clocks existed then though. The oldest clocktower in Europe that still exists was built over 100 years before Galileo was born, and time measurement existed longer than that. You can measure time fairly accurately with water clocks which had been known for thousands of years before Galileo. Not having “modern” pendulum clocks yet doesn’t mean that they didn’t have any way to measure time. Even without water clocks you can get decently reliable measurements of time with rhythmic chants (think how today we might say "one Mississippi, two Mississippi, etc.). Early alchemical recipes often include time measurements in chanting a specific prayer or passage a certain number of times during a specific step. Sure you’re not going to get milisecond level accuracy this way but you don’t really need that for a lot of things. Hero of Alexandria built mechanical automata 1500 years before Galileo using pulleys and weights as timers. Time measurement not only existed before pendulum clocks, it was pretty decent.
With same gravity constance everything fall down at the same speed, but only in a vacuum. In an atmosphere there count the air resistance of an object, even if they are made of the same material and weight, an iron sphere of 1 kg fall faster than a iron sheet of 1 kg.
That’s why Gallileo’s balls were so special.
With two metal balls, one solid and one hollow, you could rule out the role of resistance?
I assume you mean keeping the outer diameter the same and making one ball lighter than the other. That’s clever, it would eliminate aerodynamism as a factor.
However wouldn’t results still vary, since hollowing out the metal ball increases its buoyancy ? (Archimedes’ principle).
They would have the same coefficient of drag, correct, but the air resistance would end up having more effect on the lighter mass of the hollow sphere, so it would be slightly slower to fall.
Archimedes principle here is accounted for in the different weights. Everything that you can put on a scale is already being acted on by Archimedes principle in air.
Except if you could measure exactly the speed of objects falling in a vacuum, the heavier object would appear to fall faster due to the gravitational pull on the Earth. You’re forgetting the Earth falls toward the object too.
No, mass or weight of an object is irrelevant, in one of the jurney to the Moon, astronauts demostrate it with an hammer and a feather on the moon that both fellt at the same speed. It exist one gravity aceleration, on earth is 9,82 ms², which is the force of acceleration which experiment any object on Earth, the only difference which can slow it down is the resistant of air, this can be different in each object, but without atmosphere there is nothing which slow down the acceleration of the object, it’s irrelevant the material, weight, mass or form. Basic physic
www.youtube.com/watch?v=Oo8TaPVsn9Y
The difference is far too small to measure at these scales, the Earth would be falling toward the more massive object faster than the less massive object. Therefore the more massive object hits first.
It has nothing to do
Only technically. The effect you’re describing is so minute that it’s insignificant.
It’s like pointing out that the Great Pyramids of Giza are so massive that time moves 1 billionth slower for the surrounding objects. It’s neat that the effect is potentially measurable, but noone is going to be adjusting their clocks to account for it
Science is built on technicalities. In an exam, if a student considered the centre of m_1 as the centre of gravity instead of the weighed centre of m_1 and m_2 they would fail. This is no different
Your analogy doesn’t hold up, because factors get ignored in physics discussion all the time. Whem was the last time you’ve see a question in a dynamics class that didn’t ignore air resistance for the sake of simplicity?
The effect you’re describing is orders of magnitude smaller than that. I doubt the change would even register in a double floating-point variable if you did the calculations in Matlab
Only for tiny masses…
Compared to the mass of the Earth, yes, we’re dealing with tiny masses
No en.m.wikipedia.org/wiki/Equivalence_principle
.
R^2 is on the bottom. We don’t ignore the mass of one object because it’s insignificant, that would make the top of that equation 0 and the object wouldn’t fall at all.
That nifty gravitational law gives you the force of gravity on an object, not the acceleration. Force also equals mass times the resultant acceleration, right? So Fg1 = m1*A1 = G*M*m1/r^2 and Fg2 = m2*A2 = G*M*m2/r^2. m1 and m2 are present on both sides of those equations, respectively, so they cancel, and you get A1 = G*M/r^2 and A2 = G*M/r^2, which are identical. The mass of an object affects the force of gravity, but when you look at acceleration the mass terms cancel out.
You’re right, I had it wrong. Misinformation deleted.
No worries, no big deal
People have mentioned air resistance but the four elements also works as an early model of the states of matter.
there are more states
Yeah but as an ancient dude you can observe the classic 4 easily.
Did you know that two identical triangles are identical to each other
But what about three identical digons?
<img alt="" src="https://lemmy.world/pictrs/image/3ca6ff32-de2c-4cc3-81b4-8b9f933a176d.jpeg">
Try dropping your phone from a hot air balloon and see which one hits the ground first.
A hot air balloon masses a lot but weighs nothing
Theres a yo’ mama joke in there somewhere.
If you want to be pedantic, it weighs less than nothing.
If you want to be really pedantic, it weighs a lot, but the upward buoyant force from Archimedes’ principle counteracts it completely, and then some.
Let’s argue “what in heavy” before we go there
www.usgs.gov/…/how-much-does-a-cloud-weigh
Planes, helicopters- lots heavy stuff not falling faster than lighter ones
You can find exceptions, but on average, heavier objects will fall very slightly faster than light ones, because they excert their own gravity field onto Earth and therefore pull it towards themselves.
This requires a somewhat unintuitive definition of “falling”, in that both the object and Earth itself moves, but given that any object with mass excerts a gravitational field, there is not actually any other definition.
No.
en.m.wikipedia.org/wiki/Equivalence_principle
Wut? This does not turn off gravitational pull for objects other than Earth.
Or I’m misunderstanding what you’re trying to say, but yeah, no clue.
You didn’t read it, it is literally telling you you are wrong.
Ah, I’m not saying there’s a different force being applied to feather vs. hammer. The meme above doesn’t mean that they “fall faster” in the sense that the hammer falls at a higher velocity. It’s rather colloquial usage of “faster” to mean “finishes sooner”. Because what does happen, is that the hammer collides sooner with Earth, since the hammer pulls the Earth towards itself ever-so-slightly stronger than the feather does.
I guess, for this to work, you cannot drop hammer and feather at the same time in the same place, since they would both pull Earth towards themselves with a combined force. You need to drop them one after another for the stronger pull of the hammer to have an effect.
So, this is also going off of this formula:
But setting
mass_1as Earth’s mass andmass_2as either the feather’s or hammer’s mass. A highermass_2ultimately leads to a higher force of attractionF.So in that equation, let’s say mass 1 is earth. G and distance will be equal in both instances of dropping.
Rewrite equation:
Distance^2/ G*mass 1 = mass 2 /force
And
Distance^2/ G*mass 1 = mass 3 /force
Therefore,
Mass 2 /force = mass 3 /force
F = m*a
Mass 2 / mass 2*a = mass 3 / mass 3 * a
This cancels out to show that a = a, their acceleration is the same.
Depends on whether or not you count in air resistance. I was just making a shitpost
Interesting way to admit you were wrong
Something something friction
I am most certainly not a science whiz but it’s so goddamn funny to see this whole comment section full of people just… explaning and correcting each other poorly with varying degrees of correctness. Just like 50 half-true and misremembered tidbits from everyone’s intro to high school physics class, blindly seeking targets in space. I promise you guys, there’s a very straight answer to this like two or three clicks away, written more clearly and succinctly than anyone here is managing to do.
Don’t tell them that. You’re contaminating my petri dish. ;)
Lemmy (or most social media) in a nutshell.
I have noticed there is a bit of a more “anti intellectual” bent on Lemmy compared to Reddit. Like there is a lot of stupidity on reddit but usually someone comes in with actual knowledge. On Lemmy I just see people arguing in circles with each other with nobody ever actually looking anything up.
actually your wrong
You’re*
FTFY
stop bullying me 😭
I can’t, you’re being intellectual on lemmy and we have an anti-intellectual bent here. I am compelled by the lemmy force to do this again.
IMO, it’s okay to have casual conversations without being an expert or researching every post. Redditors’ habit of fact-checking everything is honestly tiring. Conversation has other purposes besides education. I think many people are looking more for human interaction than for correct facts.
Right but conversations about science where all parties are wrong and nobody is willing to actually look shit up are completely pointless. It’s the exact same problem that caused the situation in the OP in the first place.
Be careful with that, actually. Reddit mastered repeating an explanation or analogy they read on another thread or saw on YouTube, but being quite eloquent at explaining it. Problem is, if they misunderstood it to begin with, they’ll just as confidently repeat a broken version.
I didn’t notice it at first… then I started seeing explanations for things on my field and cringed at how wrong they were, and then I started noticing the pattern and the very repeated analogies on other areas too.
~ Rosencrantz & Guildenstern Are Dead
Brilliant, brilliant film.
The four phases of matter! Solid liquid gas and plasma!
Wait… What about the other 16 phases?! Those are the cool ones
Ice I, ice II, … all the way to Ice XVI!
Brian Cox visits the world’s biggest vacuum | Human Universe - BBC
To be fair to Archimedes, heavy objects do usually fall faster than light ones*, and to be fair to Newton, stuff coming towards you usually has a higher relative velocity than things going away from you.+
*You need your objects to be weigh a lot relative to their air resistance to notice otherwise.
+You need some pretty ambitious equipment to detect that electromagnetic radiation such as light does not follow this pattern.
If you like novels I highly recommend Galileo’s Dream by Kim Stanley Robinson. It has a moment where Galileo realizes you could “weigh” time, in his experiments with objects rolling down an inclined plane.
Aristotle said so much dumb shit, like he said that women have less teeth and never bothered to check
What if a planet that is Earth-sized falls down on Earth from let’s say 5-10 meters though?
It would fall at 2g, because two Earth-sized masses attract each other in that case. With smaller objects it’s just 1g, because the mass of, let’s say, a nice cup of tea is negligible compared to the mass of Earth.
A thing that size would have initial velocity to begin with,
But acceleration does not depend on mass, (which is kinda weird from an earthling’s perspective), which Einstein formalized in an amazingly powerful theory called General Relativity
Straight to jail.
Do not pass go. Do not collect
M200These days, everything seems to be made out shit & piss.
Everything is made all of those in combinations and varied quantities at the molecular level
TBF it took awhile to work out vacuum chamber technology, and some people did throw some spherical stuff off the tower of pisa at one point.