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Posted: 7/31/2018 2:34:12 PM EDT
[#1]
Quote HistoryQuoted:
Energy is defined as force times displacement. It the force doesn’t move what it is acting upon, then it isn’t energy. It’s just a force. How is that any different than me pushing down on the scale causing the same inaccurate reading. When I push on that scale I use energy, so how is a magnet doing the same thing “not using energy”. |
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Posted: 7/31/2018 2:34:39 PM EDT
[#2]
If motion is relative, will spinning a full bucket of water in infinite, empty space spin all the water out of it? How does the bucket know it's in motion?
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Posted: 7/31/2018 2:34:50 PM EDT
[#3]
IN for the answers, I think I slept through that Physics lecture.
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Posted: 7/31/2018 2:36:04 PM EDT
[#4]
Quoted:
Then how do magnets work? How can I put a magnet on my refrigerator and it not fall off? Wouldn’t it use magnetic energy to pull itself to the fridge to resist gravity? So how come it never falls off? |
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Posted: 7/31/2018 2:37:39 PM EDT
[#5]
Quote HistoryQuoted:
Ok a lot of people are saying it’s not moving so therefore there is no energy being used, whick ok I get that. But it still doesn’t seem to apply here because the magnet is using its magnetic field to pull itself and with a rare earth magnet it pulls itself with enough force you could get an inaccurate weight many times what it truely weighs. How is that any different than me pushing down on the scale causing the same inaccurate reading. When I push on that scale I use energy, so how is a magnet doing the same thing “not using energy”. Quote HistoryQuoted:
Quoted:
Energy is defined as force times displacement. It the force doesn’t move what it is acting upon, then it isn’t energy. It’s just a force. How is that any different than me pushing down on the scale causing the same inaccurate reading. When I push on that scale I use energy, so how is a magnet doing the same thing “not using energy”. 
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Posted: 7/31/2018 2:38:16 PM EDT
[#6]
 Fuckin' magnets, how do they work? |
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Posted: 7/31/2018 2:40:06 PM EDT
[#7]
It’s a vacuum
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Posted: 7/31/2018 2:41:30 PM EDT
[#8]
Quote HistoryQuoted: Yes and because there is no work there is no heat. Therefore the magnet doesn't cook aand thus stays in it's raw state, stuck forever. Why do you think they call it a "rare Earth magnet?" Duh. |
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Posted: 7/31/2018 2:42:46 PM EDT
[#9]
The one example I like to share with my students is, “the next time you sit around a campfire, remember that the flame/ heat is just stored sunshine.
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Posted: 7/31/2018 2:43:59 PM EDT
[#10]
Quote HistoryQuoted:
Lets say the magnet loses over half of it's magnetism. Is it considered medium well? Very good inductive reasoning but that would only be medium. It becomes medium well after it loses three quarters. |
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Posted: 7/31/2018 2:46:01 PM EDT
[#11]
People can define force and energy but I think what you're really asking is why there's an electromagnetic force and what it actually is under the hood.
Well, that is the $1mil question. We can describe how it works all day long but nobody actually knows what it is because it gets down into quantum behavior, virtual photons and such, and we simply haven't figured it out yet. |
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Posted: 7/31/2018 2:47:57 PM EDT
[#12]
You transfer kinetic energy into a piece of iron to align the molecules and magnetize it.
Or pass it through an electric field. Either way, you are storing some energy in the process. Magnetic attraction to ferrous metal, and gravity are both forces. |
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Posted: 7/31/2018 2:47:58 PM EDT
[#13]
Hey! How exactly is a rainbow made? How exactly does a sun set? How exactly does a posi-trac rear-end on a Plymouth work? It just does.
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Posted: 7/31/2018 2:56:11 PM EDT
[#14]
Quote HistoryQuoted:
Hey! How exactly is a rainbow made? How exactly does a sun set? How exactly does a posi-trac rear-end on a Plymouth work? It just does. 
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Posted: 7/31/2018 3:03:07 PM EDT
[#15]
The normal force of the fridge induced by the magnet results in a static frictional force stronger than the gravitational force on the magnet.
The magnetic field is exerting a continuous force, just like gravity, but it takes no energy to hold the object stationary because it isn't moving. Force is being applied but no energy is changing hands. If you hold a ten pound weight off the ground, the force your body is applying and the force of gravity cancel, and apparently no work is being done because nothing is moving. Except at the molecular scale, your skeletal muscles are using chemical energy (ATP) to push myosin around, motor neuron action potentials are running around and acting on muscle fibers, .ect. , (doing work), so on the macro-level things are stationary but on the molecular-level your body is subconsciously expanding, contracting and doing lots of other stuff many times a second. The object is bobbing up and down slightly, thus accelerating and you're doing work on the object and yourself to keep it "stationary", which is why you can't hold it forever. The human body is not designed to exert continuous force. A brick could though. Or a magnet. Or a table. Energy is not force and magnetics are basically tables. We good? |
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Posted: 7/31/2018 3:06:28 PM EDT
[#16]
Quote HistoryQuoted:
I have only had to refill my magnet twice |
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Posted: 7/31/2018 3:06:49 PM EDT
[#17]
Quote HistoryQuoted: How is it equal? The magnet is sideways actively resisting the pull of gravity. If I leave the magnet up for 2 mins it uses less energy than if I left it up there 2 years? Mike |
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Posted: 7/31/2018 3:10:13 PM EDT
[#18]
Quote HistoryQuoted:
If motion is relative, will spinning a full bucket of water in infinite, empty space spin all the water out of it? How does the bucket know it's in motion? Mike |
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Posted: 7/31/2018 3:12:43 PM EDT
[#19]
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Posted: 7/31/2018 3:13:56 PM EDT
[#20]
It will eventually falloff when it runs out of electrons or protons or something that magnets shed. I know magnets slowly lose strength and can be re-magnetized.
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Posted: 7/31/2018 3:14:57 PM EDT
[#21]
Quoted:
Then how do magnets work? How can I put a magnet on my refrigerator and it not fall off? Wouldn’t it use magnetic energy to pull itself to the fridge to resist gravity? So how come it never falls off? |
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Posted: 7/31/2018 3:16:29 PM EDT
[#22]
Quote HistoryQuoted: Yep no energy used. It is the way the atoms are made up that form the attraction. 1) is it cooled to absolute zero? 2) do you even Brownian motion? 3) are electrons moving in their orbits? what's not moving? |
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Posted: 7/31/2018 3:21:08 PM EDT
[#23]
Brb, gotta jack my truck up off the ground so my springs dont wear out, then I can post my reply.
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Posted: 7/31/2018 3:21:13 PM EDT
[#24]
It doesnt fall off because your refrigerator is producing an electromagnetic field.
If you lose power or unplug it.... well, your magnets will fall off. |
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Posted: 7/31/2018 3:21:15 PM EDT
[#25]
Is high school science class not a thing anymore? It was a required class when I went to school back in the fucking dark ages before home computers or the interwebz.
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Posted: 7/31/2018 3:25:38 PM EDT
[#26]
Quote HistoryQuoted:
Wrong. Energy cannot be destroyed or created (we think), and matter is merely a form of energy. Twist energy into enough knots and you get matter (strings). Smack matter hard enough and it returns to being energy. Quote HistoryQuoted:
Quoted:
Matter op, matter cannot be created or destroyed. Like put two apples together, one of matter, the other antimatter and the explosion would finally be worthy of all the Snackbars screamed when someone farts. |
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Posted: 7/31/2018 3:29:44 PM EDT
[#27]
There are 2 types of energy, Kinetic and Potential. Magnetism is a type of Potential energy.
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Posted: 7/31/2018 3:31:04 PM EDT
[#28]
Quote HistoryQuoted:
There are 2 types of energy, Kinetic and Potential. Magnetism is a type of Potential energy. |
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Posted: 7/31/2018 3:31:37 PM EDT
[#29]
Quote HistoryQuoted:
There are 2 types of energy, Kinetic and Potential. Magnetism is a type of Potential energy. |
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Posted: 7/31/2018 3:32:05 PM EDT
[#30]
Came here hoping for a magnet on a treadmill reference.
Left disappointed. 
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Posted: 7/31/2018 3:39:54 PM EDT
[#31]
i'll take aligned electron moments for $1000 Alex
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Posted: 7/31/2018 3:41:18 PM EDT
[#32]
Quote HistoryQuoted:
I have only had to refill my magnet twice |
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Posted: 7/31/2018 3:43:23 PM EDT
[#33]
Quote HistoryQuoted:
How is it equal? The magnet is sideways actively resisting the pull of gravity. If I leave the magnet up for 2 mins it uses less energy than if I left it up there 2 years? Quote HistoryQuoted:
Quoted:
Beacause the energy you exerted to pull the magnet off the refrigerator is reciprocal to the energy it constantly exerts to stay in place. It's a weird balance of nature I suggest taking physics and/or Thermodynamics courses. If you're into these kinds of questions, you'll love these courses. |
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Posted: 7/31/2018 3:45:19 PM EDT
[#34]
Quote HistoryQuoted:
You transfer kinetic energy into a piece of iron to align the molecules and magnetize it. Or pass it through an electric field. Either way, you are storing some energy in the process. Magnetic attraction to ferrous metal, and gravity are both forces. |
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Posted: 7/31/2018 3:46:38 PM EDT
[#35]
Quote HistoryQuoted:
There are 2 types of energy, Kinetic and Potential. Magnetism is a type of Potential energy. It's not something I've researched but I would say magnets are a mix of potential and kinetic energy |
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Posted: 7/31/2018 3:47:15 PM EDT
[#36]
Quote HistoryQuoted:
Work = force x distance. Neither the magnet nor the refrigerator are moving -> no work -> no energy is used. You should read a Physics book someday. |
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Posted: 7/31/2018 3:54:29 PM EDT
[#37]
Energy is only expended through work (force acting over a distance). Stationary force does not expend energy.
Mike PS. Strictly speaking conservation of energy is not axiomatic but a result of symmetry. When the equations of motion are unchanged with translation through space, conservation of momentum is just a mathematical consequence. When the equations of motion are unchanged by rotation, angular momentum is conserved. Equations of motion unchanged in time give rise to energy conservation. With space expanding at an ever-increasing rate dark energy is being created. For now conversation of energy holds on a galactic scale but not in the spaces between galexies. |
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Posted: 7/31/2018 4:16:05 PM EDT
[#38]
Quote HistoryQuoted:
Energy is only expended through work (force acting over a distance). Stationary force does not expend energy. Mike PS. Strictly speaking conservation of energy is not axiometric but a result of symmetry. When the equations of motion are unchanged with translation through space, conservation of momentum is just a mathematical consequence. When the equations of motion are unchanged by rotation, angular momentum is conserved. Equations of motion unchanged in time give rise to energy conservation. With space expanding at an ever-increasing rate dark energy is being created. For now conversation of energy holds on a galactic scale but not in the spaces between galexies. That CoM is a consequence of homogeneity and not an assumption is an important distinction. |
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Posted: 7/31/2018 4:17:25 PM EDT
[#39]
Quote HistoryQuoted:
It does fall off because your refrigerator is producing an electromagnetic field. If you lose power or unplug it.... well, your magnets will fall off. |
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Posted: 7/31/2018 4:19:22 PM EDT
[#40]
Quote HistoryQuoted:
Wrong. Energy cannot be destroyed or created (we think), and matter is merely a form of energy. Twist energy into enough knots and you get matter (strings). Smack matter hard enough and it returns to being energy. |
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Posted: 7/31/2018 4:19:47 PM EDT
[#41]
OP this is pretty simple.
There is attractive force between the metal and the magnet. Gravity is acting (toward the center of the earth) on the magnet. Opposing that force is the force of friction. In this case, since the magnet isn't moving, it's the Static coefficient of friction between the surface of your fridge and the surface of the magnet. If the friction was incredibly low, the magnet would slide down the fridge. |
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Posted: 7/31/2018 4:23:15 PM EDT
[#42]
lol
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Posted: 7/31/2018 4:24:54 PM EDT
[#43]
Quote HistoryQuoted:
OP this is pretty simple. There is attractive force between the metal and the magnet. Gravity is acting (toward the center of the earth) on the magnet. Opposing that force is the force of friction. In this case, since the magnet isn't moving, it's the Static coefficient of friction between the surface of your fridge and the surface of the magnet. If the friction was incredibly low, the magnet would slide down the fridge. |
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Posted: 7/31/2018 4:25:05 PM EDT
[#44]
Quoted:
Then how do magnets work? How can I put a magnet on my refrigerator and it not fall off? Wouldn’t it use magnetic energy to pull itself to the fridge to resist gravity? So how come it never falls off? |
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Posted: 7/31/2018 4:26:12 PM EDT
[#45]
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Posted: 7/31/2018 4:26:55 PM EDT
[#46]
 Fucking magnets how do they work? |
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Posted: 7/31/2018 4:30:31 PM EDT
[#47]
Quote HistoryQuoted:
Fuck me. I'm feeling lighter already. Quote HistoryQuoted:
Quoted:
Quoted:
Does gravity use up gravitational energy? When will the Earth run out of it? |
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Posted: 7/31/2018 4:35:30 PM EDT
[#48]
The magnet uses a tiny amount to create the field, and field produces the force.
That "cannot be created nor destroyed" is taken out of context and way too seriously. It refers to closed systems, which really only occur in thought experiments. |
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Posted: 7/31/2018 4:35:31 PM EDT
[#49]
Quote HistoryQuoted:
If energy can’t be created or destroyed then that means the energy of the universe is finite and didn’t change. That also means that energy was contained in a singularity that went bang. |
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Posted: 7/31/2018 4:38:50 PM EDT
[#50]
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