- #1
uperkurk
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Why is it impossible to sit in a chair and lift it up? People can lift hugh amounts of weight so why can't they lift up the chair when seated in it?
Lifting yourself up while seated
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In summary, it is impossible to sit in a chair and lift it up. People can lift hugh amounts of weight so why can't they lift up the chair when seated in it? People can lift hugh amounts of weight so why can't they lift up the chair when seated in it?People can lift hugh amounts of weight so why can't they lift up the chair when seated in it? If you lift something heavy, you push the object up, while at the same time pushing the Earth down. My neighbor used to do pullups with iron weights strapped over his shoulders. I suppose he could have strapped a chair to his posterior as well...it indeed is possible, provided that you strap yourself to the
- #2
russ_watters
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Given that you have provided no constraints, it is absolutely possible!
- #3
uperkurk
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Well I was looking for some technical explanation reallly... all I know is that it's impossible because given the force you apply to try and lift yourself, you end up pushing yourself downwards and balancing the force out?
- #4
I like Serena
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If you lift something heavy, you push the object up, while at the same time pushing the Earth down.
This way you increase the distance between the object and the earth.
If you lift up a chair while seated in it, you push the arm supports up, while at the same time pushing the seat down.
This means that you pull the chair apart, instead of lifting it up.
This way you increase the distance between the object and the earth.
If you lift up a chair while seated in it, you push the arm supports up, while at the same time pushing the seat down.
This means that you pull the chair apart, instead of lifting it up.
- #5
Flustered
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Would the same explanation go with the problem, of 2 people trying to pick each other up at the same time. Why don't they levitate?
- #6
Waterfox
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Off topic, but I just have to post this:Flustered said:
http://bbsimg.ngfiles.com/1/21873000/ngbbs4ca94cfa070d9.jpg
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- #7
Dauden
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Flustered said:
Yes that explanation does work in that situation. You lift the other person up while pushing yourself down thus "pulling apart" the connection between you and the other person. Study of Newton's Third Law of Motion is extremely valuable in understanding this topic.
- #8
Flustered
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What if both people weight 100 lbs and they both pulled up on each other with the same exact force. Which one would get lifted? Would nobody get lifted? or would they both lift?
- #9
jim hardy
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Who says they can't ?
My neighbor used to do pullups with iron weights strapped over his shoulders.
I suppose he could have strapped a chair to his posterior as well...
- #10
kurtlesker
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it indeed is possible, provided that you strap yourself to the chair.
you need first make sure that your arms have the strength to lift your own weight plus that of the chair (hit the gym?)
then get a pair of crutches, or anything that's taller than the height from the floor to where your arms are. Then just push down on the support. Chair will be lifted up with your body...
you need first make sure that your arms have the strength to lift your own weight plus that of the chair (hit the gym?)
then get a pair of crutches, or anything that's taller than the height from the floor to where your arms are. Then just push down on the support. Chair will be lifted up with your body...
- #11
kurtlesker
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depends on where you push.
If you push anywhere on the chair itself, the forces would balance out.
If you directly push the ground, like with crutches or something else that touches the ground but does not touch the chair, then it is possible, assuming that you are strong enough.
If you push anywhere on the chair itself, the forces would balance out.
If you directly push the ground, like with crutches or something else that touches the ground but does not touch the chair, then it is possible, assuming that you are strong enough.
- #12
OCR
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kurtlesker said:
Naaa, you don't need crutches, kurtlesker...
Just grab your hair, and pull... lol
The straps on boots, work about the same...
http://en.wikipedia.org/wiki/Bootstrapping
OCR
- #13
Sefrez
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If you compress a spring and wrap string around the ends where it is kept compressed, it can't propel itself! At least not when you consider the system being both the spring and the string - the forces are internal. Now cut the string, they will both be propelled, relative to each other.
- #14
SHISHKABOB
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it's because you're sitting on it
pay attention to what your bottom does if you go and try to lift a chair while you're sitting on it, or pay attention to what your legs feel like.
Or go and try and pick it up when not sitting on it. You should notice that your feet push harder into the ground when you pick it up.
stand on a scale when you try and lift something reeaaally heavy like a car. You will never actually lift the car off the ground, but you will see that the weight read by the scale increases as you try to lift the car. It's all just Newton's third law of motion.
pay attention to what your bottom does if you go and try to lift a chair while you're sitting on it, or pay attention to what your legs feel like.
Or go and try and pick it up when not sitting on it. You should notice that your feet push harder into the ground when you pick it up.
stand on a scale when you try and lift something reeaaally heavy like a car. You will never actually lift the car off the ground, but you will see that the weight read by the scale increases as you try to lift the car. It's all just Newton's third law of motion.
- #15
Flustered
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My question about the 2 people who weigh 100lbs and they both lift with the same force. Who gets picked up first?
- #16
I like Serena
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Flustered said:
Neither.
The forces they both apply cancel each other out.
And if one is stronger than the other, the other will have to let go and get lifted.
- #17
SHISHKABOB
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Flustered said:
it doesn't matter how they do it, the force that person A applies to B in order to lift them pushes himself (A) downwards. The force that person B applies to A in order to lift them pushes himself (B) downwards.
Since they both weigh the same, the force applied by each to the other will be equal, and thus the forces pushing each of them down will be equal to the other force trying to push them up!
go find a friend and try it out and try and get a sense for why it doesn't work
- #18
jim hardy
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Dont you guys remember trying this when you were toddlers?
I remember vividly at about age 3 pulling up on the seat of my pants believing i'd fly to the ceiling any second.
I remember vividly at about age 3 pulling up on the seat of my pants believing i'd fly to the ceiling any second.
- #19
OCR
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jim hardy said:
You were just too young to have enough "pucker power", jim.
Kristofferson claims that Sky King did... "have enough".
Ok, ok, the situation was not quite the same for Sky, and it helps to have some collective knowledge about helicopters...
http://www.copters.com/aero/autorotation.html
http://en.wikipedia.org/wiki/Autorotation_(helicopter)
OCR... lol
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- #20
uperkurk
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Newtons third law. Thanks for clearing that up, I think of some random things sometimes lol
1. How can I lift myself up while seated?
To lift yourself up while seated, you can use your arms and leg muscles. Place your hands on the armrests or the side of the chair and push down while also pushing up with your legs. This will help you lift your body up off the chair.
2. Is it safe to lift myself up while seated?
It is generally safe to lift yourself up while seated, as long as you do not have any pre-existing medical conditions or injuries that may be aggravated by this movement. If you are unsure, it is always best to consult with a medical professional before attempting to lift yourself up while seated.
3. Can I use a chair with wheels to lift myself up?
It is not recommended to use a chair with wheels to lift yourself up. This can be dangerous as the chair may roll or tip over, causing injury to yourself. It is best to use a sturdy, stationary chair or surface for this movement.
4. What muscles do I need to use to lift myself up while seated?
You will primarily be using your arm and leg muscles to lift yourself up while seated. This includes your biceps, triceps, chest, and leg muscles such as your quadriceps and glutes. It is important to engage these muscles and use proper form to avoid injury.
5. How can I modify the lift if I have limited mobility or strength?
If you have limited mobility or strength, you can modify the lift by using a chair or surface with armrests and pushing down on the armrests while also pushing up with your legs. You can also use a higher surface, such as a countertop or table, to make the lift easier. If you are still struggling, it is best to seek assistance from a caregiver or medical professional.
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