Things you always wanted to know the answer to [Vol. 2]
Discussion
Hooli said:
paul.deitch said:
What is the likely maximum number of animals, horses, elephants, oxen, even men etc that you can harness together to do USEFUL work? I was just thinking about how they might have built the Pyramids...
All of them.Ayahuasca said:
Hooli said:
paul.deitch said:
What is the likely maximum number of animals, horses, elephants, oxen, even men etc that you can harness together to do USEFUL work? I was just thinking about how they might have built the Pyramids...
All of them.
Basketball - is height the be-all-and-end-all for players?
I never really followed it, but in the 90s I took a bit of interest and whilst there were always tall players, there we also more normal sized ones - well, 6' 2" - 6' 4", nowadays I occasionally see posting on FB from my Yank Sports mad mate about this signing who's 7' 6" - it seems 7 footers are the new norm, but they must be a tiny, tiny fraction of the population.
So are the NBA just looking for the tallest men in the US and worrying about skill later, or would say a tiny little 5' 10" bloke like me have a change if I was talented enough?
I never really followed it, but in the 90s I took a bit of interest and whilst there were always tall players, there we also more normal sized ones - well, 6' 2" - 6' 4", nowadays I occasionally see posting on FB from my Yank Sports mad mate about this signing who's 7' 6" - it seems 7 footers are the new norm, but they must be a tiny, tiny fraction of the population.
So are the NBA just looking for the tallest men in the US and worrying about skill later, or would say a tiny little 5' 10" bloke like me have a change if I was talented enough?
P-Jay said:
Basketball - is height the be-all-and-end-all for players?
I never really followed it, but in the 90s I took a bit of interest and whilst there were always tall players, there we also more normal sized ones - well, 6' 2" - 6' 4", nowadays I occasionally see posting on FB from my Yank Sports mad mate about this signing who's 7' 6" - it seems 7 footers are the new norm, but they must be a tiny, tiny fraction of the population.
So are the NBA just looking for the tallest men in the US and worrying about skill later, or would say a tiny little 5' 10" bloke like me have a change if I was talented enough?
Obviously height is a major and distinct advantage and tall people will generally be pushed towards it in high school but you don't have to be tall to be a professional NBA player. http://en.m.wikipedia.org/wiki/Muggsy_BoguesI never really followed it, but in the 90s I took a bit of interest and whilst there were always tall players, there we also more normal sized ones - well, 6' 2" - 6' 4", nowadays I occasionally see posting on FB from my Yank Sports mad mate about this signing who's 7' 6" - it seems 7 footers are the new norm, but they must be a tiny, tiny fraction of the population.
So are the NBA just looking for the tallest men in the US and worrying about skill later, or would say a tiny little 5' 10" bloke like me have a change if I was talented enough?
Some years back on Call My Bluff (10-15 years 
), they had an old English word for a locker loop - the small strip of material that you get just below the yoke of a shirt - however, no one in our house can remember the word!
I have no other information about the word, what it starts with, where it came from, just that it was on Call My Bluff...
Any ideas?
), they had an old English word for a locker loop - the small strip of material that you get just below the yoke of a shirt - however, no one in our house can remember the word!I have no other information about the word, what it starts with, where it came from, just that it was on Call My Bluff...
Any ideas?
StevieBee said:
What is it about forward motion that makes it easy to balance on a bicycle or motorbike, something that can't be achieved when stationary?
http://en.wikipedia.org/wiki/Gyroscopeand
http://en.wikipedia.org/wiki/Bicycle_and_motorcycl...
Basically the wheel acts as a flywheel and the inertia provides a constant momentum around an axle which resists turning moments, hence the need for large levers (handlebars) or mechanical assistance (power steering).
StevieBee said:
What is it about forward motion that makes it easy to balance on a bicycle or motorbike, something that can't be achieved when stationary?
It's Gyroscopic force of the wheels that keeps you upright rather than the momentum - you can really feel weight differences on mountain bike wheels / tyres, lighter ones accelerate really quickly but get all skittish in over rough ground - even if the tyres are the same but the wheels different you can feel the difference in grip. Sometimes "speed is your friend" over really rough bits, the hard bit is telling your brain that 30mph will see you through a rock section and 20mph won't - when all your brain wants to do is about 5mph...
I thought gyroscopes work by having most of their mass in the rim. A bicycle rim weighs very littele and I doubt the gyroscopic forces are what is keeping the bike upright. More likely it is that the bike in motion is constantly steered to keep the centre of gravity over the wheels. You could try an experiment - lock the handlebars so there is no steering and ride as fast as you can to maximise the gyro forces. See how long you stay upright. My guess - not that long.
Ayahuasca said:
I thought gyroscopes work by having most of their mass in the rim. A bicycle rim weighs very littele and I doubt the gyroscopic forces are what is keeping the bike upright. More likely it is that the bike in motion is constantly steered to keep the centre of gravity over the wheels. You could try an experiment - lock the handlebars so there is no steering and ride as fast as you can to maximise the gyro forces. See how long you stay upright. My guess - not that long.
Proper scientific paper (peer reviewed and published) on the topic : http://fisica.ciencias.uchile.cl/~gonzalo/cursos/M...marshalla said:
Ayahuasca said:
I thought gyroscopes work by having most of their mass in the rim. A bicycle rim weighs very littele and I doubt the gyroscopic forces are what is keeping the bike upright. More likely it is that the bike in motion is constantly steered to keep the centre of gravity over the wheels. You could try an experiment - lock the handlebars so there is no steering and ride as fast as you can to maximise the gyro forces. See how long you stay upright. My guess - not that long.
Proper scientific paper (peer reviewed and published) on the topic : http://fisica.ciencias.uchile.cl/~gonzalo/cursos/M...One of the giveaways was someone made bike that looked a bit like a scooter, with tiny 1 inch-ish diameter wheels, and it would still stay upright if you gave it a shove so there are other forces at play.
TheEnd said:
Yep, it's something else.
One of the giveaways was someone made bike that looked a bit like a scooter, with tiny 1 inch-ish diameter wheels, and it would still stay upright if you gave it a shove so there are other forces at play.
Angular momentum?One of the giveaways was someone made bike that looked a bit like a scooter, with tiny 1 inch-ish diameter wheels, and it would still stay upright if you gave it a shove so there are other forces at play.
Small low mass wheel spinning very quickly vs larger higher mass wheel can spinning slower, both still have same angular momentum?
Given that at very slow speeds you can still balance fine - it isn't always the gyroscopic effect surely.
As I watched the kids learn it looked like turning the handlebars had the effect of switching most of their weight from one side to the other (or back to centre) very rapidly and bringing them back on course.
So if you are tilting right you actually steer harder to the right to bring your mass back over the centre.
Hence why learning with stabilisers is such a disaster.
The balance bike kid will have built muscle memory that naturally brings him back upright by turning the handlebars.
The poor kid with stabilisers has literally no experience of this since those bikes don't lean.
Sure they know how to pedal but that doesn't help when you are face down in the mud!
As I watched the kids learn it looked like turning the handlebars had the effect of switching most of their weight from one side to the other (or back to centre) very rapidly and bringing them back on course.
So if you are tilting right you actually steer harder to the right to bring your mass back over the centre.
Hence why learning with stabilisers is such a disaster.
The balance bike kid will have built muscle memory that naturally brings him back upright by turning the handlebars.
The poor kid with stabilisers has literally no experience of this since those bikes don't lean.
Sure they know how to pedal but that doesn't help when you are face down in the mud!
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