Yep, I was wrong on that one. Afterward I went and looked at solutions other people had and saw my mistake.

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.

My son asked, "Is this normal motion or fast motion?"

They've hooked up a power source to the orange which is why it is cooking as it sits there and starts spilling liquid on the table.

I was waiting for the reveal and disappointed that they didn't show what it was hooked up to.

It would have been so funny if Hillary would have dropped by for a cameo when Steven was doing the woodland creature calls.

Is there a Swedish word for a body part that sounds like aerosol?

Paddle boarding is hard enough.

Made me think of this song. Which I was surprised to find wasn't sifted yet.

http://videosift.com/video/Cashews-come-from-a-fruit

Pull don't push

Soo.. she's singing country music now?

The part I don't like about things like this is when people want to lie to their kids and get mad at your kids for telling their kids the truth.

It looked more like a wire saw. Maybe there was a translation issue between chain and wire.

A lot of those maps looked really familiar.

It's funny how many clips they showed of rocket jumps. I'm guessing someone worked a long time to get that mechanic working like they wanted.

They probably will...