3) it moves backwards because the force is applied to the entire system/bicycle. The wheel going backwards turns the gears and chain, rotating the pedal 'forwards' (rotating it in reverse). Because the wheel is much larger it travels much farther back than the pedal rotates forwards, even with 1:1 gearing the pedal actually travels backwards slightly compared to the ground, but in higher gears it gets much easier.
It's because the tire is so much larger than the crank, that makes it easier to rotate the tire than the crank even at 1:1, so it goes backwards.
It's counter intuitive, but I actually checked my work and yep, my bike went backwards in all gears....no sliding needed. Try it.

I guess the hint for these is the rotational test that they show at the first.

1) A sticky object that would let go like a wall crawler that climbs down a wall would create this effect. (see below)
2) You can't. As you approach infinite speed it would get very close. (see below)
3) The bike will move forward. (see below)
4) The outside parts of the wheels that overlap the rail. Also if the train has a flywheel that is larger than the wheel size the bottom of the flywheel would also always move backwards faster than the train was moving.

1) He says "what object is inside?" so I'm not sure a liquid would count. Also a viscous liquid would flow a slow rate and would probably not stop and start. You might be able to get a viscous liquid to stop and start if you had fins, but that still might just move slowly or gain enough momentum to roll fast without any flow.

2) A little excel calculation shows that the average velocity approaches twice the initial but will never hit it.

attempted m/s - total time - average m/s
1 100 1
2 50 1.333333333
3 33.33333333 1.5
...
200 0.5 1.990049751
201 0.497512438 1.99009901

3) I'm not sure if the parameters of this experiment are explained sufficiently.

If it is allowed to slip then no matter the mechanical advantage a hard pull should always be able to get the bike to skid back and defeat friction.

If the bike is not allowed to slip on the ground then I don't understand how it could ever move backwards, the only options would be that it doesn't move at all or it moves forward.

If it can't slip then the ratio of the pedal to the wheel is what is in question. Bikes only have gear ratios higher than 1 and the crank is smaller than the tire so the tire will always rotate more than the crank thus the bike should move forward.

I don't like the train one, as all of the train is moving forward, and the flange, at only one small part of the rotation is moving backward, otherwise it's mostly moving forward faster than the train. It's messy.

1) < 1/2 full of honey or other slime
2) bike will go backwards 1/4 pedal turn (forcing the pedal to rotate forward but move backwards) regardless of gearing because the wheel rotation/travel is much longer than the pedal rotation/travel

3) (T1+T2)/2 can never equal or be less than (T1)/2...so impossible unless you can finish lap 2 before you start it

4) a small portion of the lip of the wheels, farther out than the part that rides on the rail

Side note, how did you all get the numbers mixed up? #2 is the bike, not the track.

Are you sure about that? Let's say the track is 100m for simplicity's sake and you run it at 1m/s (so 100s).
If you ran the second loop 3 times faster, you run it at 3m/s and it would take 33.3s.
So, total time and distance is 200m in 133.3s at an average speed of 1.5m/s.

I think it's impossible.

Even if you ran the second loop 100000 times faster, your total time would be 100.001s and average speed would be 1.99998m/s.

It would only ever approach 2V1.

Unless there's something about rotational velocity (as opposed to speed) that I'm missing. Quite possible, given it's been a long time since I did any physics.

But I've just developed the duck flipper 2240 that can flip up to 1120 ducks at one time with a rotational speed of 1440 degrees per second, and read the orientations of the same number of receiver ducks. This should allow at least AT&T level audio.

Some additional notes based on growing up in a wheat / corn farming family:

My family uses GMO herbicide/pesticide-resistant corn seed (Roundup Ready). It's a tradeoff, because:

1) Roundup Ready seed is somewhat expensive, especially compared to just holding on to a small amount of your own harvested crop as next year's seed.

2) Like the video mentioned, the GM seeds we used have been modified to be sterile, so the grain they produce can't be replanted. Part of the justification for that is not wanting the GM version to intermingle with unmodified strains. But, most is pure profit motivation -- they want you to be forced to buy that GM seed. I don't really see that as nefarious, just business -- but opinions differ.

3) My family discovered that for corn, we could us the GM Roundup Ready seed roughly once every 5 years while still benefiting from drastically reduced insect / plant pests. If corn is within pollination range of another less known crop plant called milo, the plants can hybridize and produce a plant called shattercane. Shattercane is essentially worthless as a food crop, but is very hardy, and can spread and in many cases outcompete the corn or milo that you really want.

Getting rid of it was a very difficult and intensive process -- until the GM seed came along. Now if we see shattercane starting to make incursions, we can plant the GM seeds the next year and then hit the field with a herbicide that kills the shattercane. It works so well that the field remains clear of the pest plants / insects for several years after that without having to use much if any herbicides / pesticides.

4) In our situation, we found that we used way less herbicide / pesticide per year on average once we started rotating in the GM seeds once every several years. That would be close to a wash, but still likely a net savings even if we used the GM seeds every year (seed companies will try to sell it to you every year). Factor in increased crop yields because of the reduced/eliminated pests, and it is a clear win.

5) I'm sort of worried about the potential for a "superbug" effect, similar to overusing / misusing antibiotics. If farmers buy into the GM seed thing 100% and use it every year, I think it will increase the chances / rate of the pests becoming resistant to the pesticides / herbicides used. That's a long-term concern, and in my opinion doesn't even come close to outweighing the "pro" side of the GM argument (at least from the perspective of my family's farm), but it is something to think about.

Yes, one wheel.
Because he has a car with a differential and the other wheel is stationary, all the rotational energy goes to the transmission, clutch, then flywheel, then crankshaft. By putting it in low gear, he gains enough mechanical advantage to spin the motor past top dead center on a cylinder and has enough battery power left to get a spark (i think he doesn't spin it fast enough to generate one), and once one cylinder fires, it spins itself up to proper rpms.
This only works on open diffs, manual transmissions, and smaller, low compression motors. You could never pull hard enough to start a big v8 like this unless your name is Magnus.

Not sure why you need a bot to flip the burger. McDonald's uses a double sided grill that comes down on top of the burgers and cooks the top at the same time. You just need a way of moving the burgers from the storage, to the grill and from the grill to the holding trays, and insure the holding trays are emptied when the food expires (compared to the usual, just rotate and hope they sell before they technically expired)... based on my time in McDonald's you could also automate the fries, as the machine already dispenses the pre-measured amount into the basket, from there it would be easy enough to move that basket right into the fryer and then out and into the tray and salt them as needed.

Wasn't easy being a planet hunter back in the day *promote

I'm looking for
1 tug
The pull of a planet
1 tell
A wobbling sun
I've searched for years
Haven't found a one
But they're out there

1 jump
In radial redshift
1 slip
Of spectral lines
They'll see if I can show them the sines

Pish tosh
Green men
Take five
Take ten

Just a little cash guys

Budget's tight
Don't fund this trash guys

I can take a hint
Better face the facts
Second-hand'll have to do

Eww
All you planet hunters at the bottom
You've got fact & fantasy entwined
Finding planets except they haven't got one

Well they gotta be forming readily
When you think about it given we've got nine

1 jump
A blip in the spectrum
1 shift of meters per second
1 graph of period power
They laugh but I'm not sour

Here goes
18 months of data
Cross & correlate it
All I gotta do is run

Pish tosh
Green men
Ah don't mind them
If only they'd look closer
Would they see a pure void
No sirree
They'd find out
There's worlds galore
To see

Make way for Pegasi
51 Pegasi

First was a world
Round an old pulsar
That's true
But the news
Is a sun-like star
With wobble
Too quick & precise
To be designed
No fluke not a spot
If you like it hot
You're gonna love this find

Pegasi 51b
Planet discovered
Orbit traced
Every 4 days
Hot as can be
Its order-Jupiter size
Was something of a surprise
Especially given its star's proximity

Pegasi 51b
It's a new era
To detect
Exoplanets
Soon there'll be three
As planet pulls on its Sun
It shifts the stellar spectrum
That's how we found 51b Pegasi

How'd a planet get so close in orbit
Cause I thought you needed ice to form it
Did it later undergo some strange migration
Star too small to be so long-pulsating
And too old to be so quick rotating
Is there any other good interpretation

This will certainly help with our funding

We got your funding
We got your funding

Got a surface of 1200 C

It's treacherous
So treacherous

If in time this new breakthrough feels mundane
Planets are common

That's proof
Of the truth
I've been telling you
This is no mean anomaly

Pegasi 51b
Planet uncovered
Round a far
Main sequence star
Spectral type G
We know its mass to be high
Half Jupiter by sine i

It's 15.61 pc from home
And it shakes our faith in how planets are formed
And its star is in Pegasus
Give it an A and thus
Label the planet as b
51 Pegasi

Plotting Doppler shifts is glacial-pace
And that astrometry never prevails
But baby you're in luck cause
Up in space
You got a planet-finder never fails

You got the power of statistics now
You got a view without an atmosphere
So no more nights spent locked up in your tower
All you gotta do is wait right here
And I say

Kepler the planet-searcher
Got a dip, no 2, no 3
We just measure brightness
Plot it out & that's transiting photometry

When your stars do this
And your curves displace
Then your star's got this
Transiting its face

Then you hit compute
And lookie here

You get good diameter data
From that dip
And orbit distance from the length of year

Well now we need this tale supported by
A ground observer with a good Échelle
We got 2000 planets certified
2000 more that only time will tell

But let's take em all, plot em out
And find out if we're really all alone
Is there a rocky world we've found no doubt
That orbits in the habitable zone
Like home?

Kepler the planet searcher
Got an Earth 452b
Part of a throng
40 billion strong

There ain't never been a field
Clever as the field
There ain't never been a field
Better than the field they call
Exoplanetology

I can show you a world
A shining shimmering planet
Found concealed in the band-shifts
Of the closest star in sight

I've found hope in the skies
And facing wonder I wonder
Could the sine wave discovered be
A planet fit for life

A whole new world
A new fantastic point of blue
Placed in that narrow zone
Where water flows
Midway tween cold & steaming

A whole new world
Its sun a faint, reddish hue
Could there be waiting here
A biosphere
Evolving in this whole new world to view

Fathoming a whole new world to view

Unbelievable find
Indescribable feeling
Earthlings someday revealing
Through directly captured light
A whole new world

Don't just stare from a far

Though nigh impossible to see

Wouldn't close up be bolder

Next to its parent's flair
If life is there
We'll know through atmosphere spectroscopy

A whole new world

Block the glare of the star

A laser starshot to pursue

With a star-shaped occulter

Chasing that crazy dream
That's always been
Of walking in a whole new world with you

a whole new world
That's where we'll be
A thrilling chase
A home in space
For you and me

you're welcome to your opinion, but there's a reason they are supposed to use the BACK of their hand rather than an open palm, and a reason why they are supposed to have a female officer conduct the search. There's no reason for the officer to have ignored those two things he's been trained to do. Cuff her, seat her, and wait.
I saw groping and rotating. I saw it again when I watched again. Her breast moved. I would vote for the plaintiff in her lawsuit against the force.

WTF?!? They still do field sobriety tests without a breathalyzer to back them up? That's moronic. They could supply the entire force with two breathalyzers each for what this one bad arrest is going to cost us.
....and WTF 2.0....
Aren't they supposed to have female officers search women. That was not a normal search either, you don't open palm the breast and rotate, that's copping a feel, not searching. Proper search method is to use the back of the hand across the under side of the breast, and maybe a pat to the middle/top if it's possible there's something hidden, not a grab and rotate.

She's going to get paid, no matter what the cops say. All her attorney has to do is ask the jury 'what if that was your wife, mother, daughter being molested over someone else's mistake?' They won't have to leave the court room to deliberate. Sadly, the cops don't seem like they'll learn a thing.

That bit about the shrimp able to reflect a photon of light with rotating polarity is wrong I think. They were probably trying to say reflecting polarized light and also able to vary the angle of polarization. So for one photon, no matter how far away you are when you detect it, it will always have the same polarization. And the photon .1sec later will have a different angle.

I drove right under the core of this thing going home. I could actually see a tornado being made and I checked all the weather and News outlets and there was nothing, except that NOAA decided to throw a Severe Thunderstorm Warning 10 minutes up AFTER IT PASSED...

It was so crazy to see a tornadic supercell in West Valley City (Salty Lake City, for most Sifters). It was following 2700 West for a bit and then I-215 (nearing the airport) was moving super fast to the NNE, straight to Washington Terrace and Riverdale. The winds were wild and the cloud formations were awesome, they were moving fast enough that I thought a partial nub might be visible where I was at, but I never did see it.

All that I saw was the main vortex with the amazing sight of all the cold air being sucked into the vortex at the SSW corner of the leading edge. Which was twisting more than fast enough to be a "horizontal twister". It was rotating so fast it was amazing; since you could see that sight you knew all it needed was a bit of air to push against it from underneath and stand up some of those vortices around the central core and then, walla, you'd get the tornado (I actually did believe that Ogden or Bountiful would get one since that was where it was heading).

All it needed was to get a little closer to the mountains and you'd have the right ingredients.

Thus, this is what you see happen right here in this video. North of my house, out in the middle of the Great Salt Lake, sits Antelope Island. It got hit by the raining part of this tornadic system but look at this wonderful storm video from it:

https://twitter.com/AntelopeSP/status/779078436568518656

It even had some golf ball hail in it.

I'm not joking. I've gotten into heated debates on multiple occasions with people on Google+ who honestly believe there is no way the Earth is not flat. At first, I couldn't believe they weren't fucking with me, but they were SERIOUS. Terrifyingly so.

You go and look at their other posts, and there are whole communities filled with certifiably crazy people talking about some seriously demented theories. NASA photos from ISS are simulated; the round earth theory is a sophisticated psy-op meant to enslave our minds; the entire universe is flat, rotates around the Earth, and gravity is somehow a lie, and every photo and video showing a round Earth is a fake.

These people are breeding, dude. In 2016. I'm terrified.