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I have learnt a new skill at this forum from Disco-Pete! More smilies. Here called spin. 😎
But shouldn't we have an anti-spin smiley too? Be useful in depicting electrons and things.
And most things in our solar system tends to spin anti-clockwise when seen from above. 😕
I was thinking about all this spinning Earth and Moon stuff. Tides on the Moon are apparently 80 times stronger than on Earth.
If the Moon had an ocean, the high tide mark would be a massive 320m above low tide, er, I think.
I also learned some new words. The Moon has dusty "Lobate Scarps" which change with the tides. Needs Lasers to measure it.
Tides | Moon in Motion – Moon: NASA Science
All very interesting.
...............................I have learnt a new skill at this forum from Disco-Pete! More smilies. Here called spin. 😎
But shouldn't we have an anti-spin smiley too? Be useful in depicting electrons and things.
And most things in our solar system tends to spin anti-clockwise when seen from above. 😕
I was thinking about all this spinning Earth and Moon stuff. Tides on the Moon are apparently 80 times stronger than on Earth.
If the Moon had an ocean, the high tide mark would be a massive 320m above low tide, er, I think.
I also learned some new words. The Moon has dusty "Lobate Scarps" which change with the tides. Needs Lasers to measure it.
Tides | Moon in Motion – Moon: NASA Science
All very interesting.
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Alan Guth has a mindblowing theory of the size of the universe,saw it on youtube last night.If you think it is big this will give you a whole new perspective.I personally cannot wrap my head around 10 to the 20 something larger than 40 billion LY.
I presume this is the Alan Guth video to which you refer, oreo?
Alan Guth - How Vast is the Cosmos? - YouTube
Alan Guth - How Vast is the Cosmos? - YouTube
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Welcome back to the 'Pub Physics' thread, Steve. 😉
There's no point in swimming against the tide on an 'Exclusive Members Club Physics' thread!
P.S. "Lobate Scarps" sounds like an underrated Star Wars character!
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So when he mentions the notion of "infinite pocket universes", is this not a direct contradiction to a beginning? Can there be a beginning to an infinite number?
That gravity thread seemed to attract Moving-Coil Cartridge Club, who are a Den of Jackals, IMO. 😀
Prefer Expanding Club.
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People can freely talk rubbish here. Because nobody knows the answer anyway.
I was nodding off a bit in that video, but woke up when Lobate Guth mentioned that Gravity is negative energy and balances out the positive energy of matter. That was new to me.
I hadn't thought about it, but Gravity is attractive where every other force else repels. So the Universe can expand without expending energy. I don't really get it though. When is matter ever made out of nothing? Never seen it happen once. 😕
Prefer Expanding Club.
.............................People can freely talk rubbish here. Because nobody knows the answer anyway.
I was nodding off a bit in that video, but woke up when Lobate Guth mentioned that Gravity is negative energy and balances out the positive energy of matter. That was new to me.
I hadn't thought about it, but Gravity is attractive where every other force else repels. So the Universe can expand without expending energy. I don't really get it though. When is matter ever made out of nothing? Never seen it happen once. 😕
It can seem strange that gravity is attractive only while the other three basic forces (electromagnetic, weak nuclear and strong nuclear) are both attractive and repulsive.
However, it is only because gravity is always attractive that we notice it at all!
Electromagnetic forces, being both attractive and repulsive, nearly cancel for macroscopic (large-scale) objects.
This allows the comparatively weak force of gravity to be the dominant force determining the motions of planets, moons, stars, and galaxies.
Nature seems to know what it is doing! 😎
99% of atom is empty Anyway . I think that play major role in why gravity is macro phenomena. There isn't much space occupied to make a significant force .
In the interests of equality and diversity, can a male skater (or indeed any of the modern variations of gender) also do the same thing?
I am interested in vishal raju's explanation of Gravity.
But can digress into Ice-Skating and Spin. Cue lovely Katerina Witt... heavy old chassis, as we all know. But made it all look easy in 1984 at Sarajevo.
Katarina Witt Wins Gold - Sarajevo 1984 Winter Olympics - YouTube
This is ARTISTRY. Only thing I ever saw better was Aljona Savchenko and Bruno Massot at the 2018 Winter Olympics. 😱
Aljona Savchenko and Bruno Massot (GER) - Gold Medal | Pairs Free Skating | PyeongChang 2018 - YouTube
Leave the heavy Men to the heavy-lifting, but light Women do spin better. Question of Mass.
But can digress into Ice-Skating and Spin. Cue lovely Katerina Witt... heavy old chassis, as we all know. But made it all look easy in 1984 at Sarajevo.
Katarina Witt Wins Gold - Sarajevo 1984 Winter Olympics - YouTube
This is ARTISTRY. Only thing I ever saw better was Aljona Savchenko and Bruno Massot at the 2018 Winter Olympics. 😱
Aljona Savchenko and Bruno Massot (GER) - Gold Medal | Pairs Free Skating | PyeongChang 2018 - YouTube
Leave the heavy Men to the heavy-lifting, but light Women do spin better. Question of Mass.
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The reason women can spin faster is they are smaller and offer a lower radius up for the conservation of angular momentum, assuming the body density of males and females is the same (which it is).
The quadruple jump - consisting of four revolutions in the air - has become a dominant force in men’s figure skating.
It may be a while before women start attempting quadruple jumps at the Olympic level, though. One challenge is that many women have hips that prevent them from contracting their bodies tightly enough to reach the necessary spin rate.
The Science of Figure Skating: Jumps
It may be a while before women start attempting quadruple jumps at the Olympic level, though. One challenge is that many women have hips that prevent them from contracting their bodies tightly enough to reach the necessary spin rate.
The Science of Figure Skating: Jumps
I think the quadruple jump may have an element of elevation involved where men have the advantage that they can jump higher, giving them more time to complete the spins.
I can throw in another factor here, which very few people know. I happen to be friends with the Master of the RNLI Hayling Island Lifeboat. 🙂
These Brave Men (and all unpaid Volunteers) interrupt their Pub drinking time to rescue drowning people off Hayling Island's treacherous Sandbar, and occasionally swimmers within Langstone Harbour.
Why should we care? Well, when the call goes out, the Lifeboatmen usually calmly finish their Pints. But if it is established that the drowning Person is dark-skinned, they leave unfinished Pints on the Bar and rush Hell for Leather for their Lifeboat.
Why? Because, according to my experienced friend the Master, dark-skinned people have a higher Mass to Volume ratio. Thus sink faster. Not many people know that.
I don't make this up. 🙂
These Brave Men (and all unpaid Volunteers) interrupt their Pub drinking time to rescue drowning people off Hayling Island's treacherous Sandbar, and occasionally swimmers within Langstone Harbour.
Why should we care? Well, when the call goes out, the Lifeboatmen usually calmly finish their Pints. But if it is established that the drowning Person is dark-skinned, they leave unfinished Pints on the Bar and rush Hell for Leather for their Lifeboat.
Why? Because, according to my experienced friend the Master, dark-skinned people have a higher Mass to Volume ratio. Thus sink faster. Not many people know that.
I don't make this up. 🙂
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Really? Then give us a reference!
Humans have a density close to 1000 kg/m^3 (the density of pure water).
That's why they float in the much denser salt water of the Dead Sea.
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Sometimes (actually quite often) you skate on thin ice @steve.
We should get back to physics. It’s too easy for what is quite an interesting thread to get waylaid with stuff that doesn’t belong here.
🙂
We should get back to physics. It’s too easy for what is quite an interesting thread to get waylaid with stuff that doesn’t belong here.
🙂
Oh come on, he's only passing on what he's heard! Can't say you guys are any different. 🙄
GO Steve! 😉
GO Steve! 😉
What I do know for a fact is: People in panic sink faster.
If you really do not know how to swim, you will panic more easily. If you somehow manage to figure out how to tread the water then you have more time.
Sometimes, a panicking person might push the rescuer down in the water to save him/her self. You are better off throwing a lifeguard ring, a small buoy or something to help them float and relax a bit and save yourself from being pushed under.
If you really do not know how to swim, you will panic more easily. If you somehow manage to figure out how to tread the water then you have more time.
Sometimes, a panicking person might push the rescuer down in the water to save him/her self. You are better off throwing a lifeguard ring, a small buoy or something to help them float and relax a bit and save yourself from being pushed under.
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I don't know why the Pub Physics thread is getting all Po-Faced about off-topicness.
As it goes, the man I referred to had a full-time job as a civilian Paramedic too.
He was also previously an Army Medic, perhaps the best one they had, so I tended to take him seriously.
Anyway, I didn't need much Physics to understand this picture:
Can't imagine little Aljona throwing Big Bruno into the air with as much grace. 😀
As it goes, the man I referred to had a full-time job as a civilian Paramedic too.
He was also previously an Army Medic, perhaps the best one they had, so I tended to take him seriously.
Anyway, I didn't need much Physics to understand this picture:
Can't imagine little Aljona throwing Big Bruno into the air with as much grace. 😀
Yeah, well. It's not entirely wrong, but it has nothing to do with mass density. Sadly, every year people drown, and the easiest to avoid drowning accidents are people who do not know how to swim. I know of some accidents with little girls wearing lots of clothing in the summer, because they've started wearing hijab, get pulled under because of the clothes even in relatively shallow water after falling in by accident... So sad.
Also some (non-gender specific) that just want to cool off and get out just a little bit too deep only to sink like a rock. We have mandatory swimming lessons in school, and there's a lot of information about swimming lessons and whatnot, but the most common reason is still a complete lack if training.
It's completely unnecessary, people just do not have enough respect for the water.
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Another reason is people only learn to swim in a swimming pool, get into a lake or the ocean with just a little bit of current and they struggle really hard to stay afloat...
Also some (non-gender specific) that just want to cool off and get out just a little bit too deep only to sink like a rock. We have mandatory swimming lessons in school, and there's a lot of information about swimming lessons and whatnot, but the most common reason is still a complete lack if training.
It's completely unnecessary, people just do not have enough respect for the water.
Edit:
Another reason is people only learn to swim in a swimming pool, get into a lake or the ocean with just a little bit of current and they struggle really hard to stay afloat...
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