Kind: captions
Language: en
[Applause]
at the palace of Discovery in Paris they
have this huge turntable where you can
sit and perform experim like in the
middle of the turntable you can put some
water and then add liquid nitrogen and
this creates a kind of fog these tiny
water droplets that spread out from the
middle but because the actual linear
speed of this turntable is increasing
the further out you go well the vapor
Falls further and further behind
creating a swirl that looks a little bit
like hurricane and that analogy is not
by accident the Earth is after all one
giant turntable and the weather patterns
we get are a result of that when you
study Physics in rotating frames of
reference or even just rotating bodies
you find some pretty mysterious and
counterintuitive phenomena which is why
I'm dedicating this video to four
revolutionary
riddles number one here I have a ramp or
an incline plane and just to show you
I'm not doing anything funny with it uh
uh if I just let a roll of tape go it
will accelerate down the ramp but here I
have a mystery cylinder and I'm going to
place that on the ramp and we will see
that it rolls and then it stops and then
it
rolls and then it stops so my question
to you is what is in the mystery
cylinder what is this
object number two uh take a bicycle and
uh have someone support it so it doesn't
fall over or lean it up against
something and then take a bit of string
and tie it to the bottom pedal now what
I'm going to do is pull backwards
horizontally on this string and I want
you to predict what the bike will do
will it go backwards forwards or will it
just stay there and not move my
intuition would tell me that it would go
forward I think it might not move if
you're going to be pulling backwards
from a stationary point on the pedal
you're going to be pulling it backwards
just as the pedals are trying to spin
the wheels forward so maybe it might not
move I think it's going to go forward
I'll go with forward you sure yeah I'm
sure all right 3 2 1 number three I want
you to think about running two laps of
this track now the first lap you can go
as slowly as you like let's call that
speed V1 but on your second lap I want
you to run faster such that the total
average speed for both laps combined is
twice V1 twice the speed of your first
lap so the question for you is how fast
do you have to run that second lap so
that your total average speed is 2
V1 number four anytime a train is moving
either slowly or very fast there is a
part of the train which is actually
moving backwards with respect to the
ground that is not backwards with
respect to the train and it doesn't have
to be going so slowly that if you ran
backwards you would be going backwards
with respect to the ground it is at any
speed any normal train will have a part
of it which is moving backwards with
respect to the ground my question to you
is which part is it now with these four
riddles you can make me a video response
if you like to tell me about your
solutions to them or you can simply
leave your answers in the comments below
and number them 1 2 3 4 so we know which
ones you're talking about and I will
post all of the answers up next week at
same time same
place all of my videos are made possible
by my patrons on patreon so if you are
one of those people thank you so much
for your ongoing support and if you're
not uh maybe now is a good time to
consider becoming one uh if you go to
patreon.com veritasium you can support
me there otherwise if you're interested
in more ridly puzzly things uh you can
check out my spinning tube trick my five
fun physics phenomena and say the
spinning disc trick and if you haven't
subscribed to veritasium already I
highly recommend you do that and since
I'll be posting the answers next week uh
I would like for you to ring the bell
down below and that will make sure that
you're notified when my videos come out
so as always thanks for watching wait
that's that's Michael's line