MegaSack DRAW - This year's winner is user - rgwb
We will be in touch
You're driving along in a car. You have a helium balloon floating around inside. As you brake for the traffic lights, which way does the balloon move?
up, its filled with helium innit.
dont tell me i'm wrong, i've seen the film 'Up'
🙂
forwards?
Jaffa Cake, anyone?
jaffa cake isnt a direction!
idiot 🙄
Is there a vacuum, a conveyor or an antelope involved?
It moves forward relative to the car / driver, which is also moving forwards. As you brake, your forward velocity falls, as does the balloons; only, the balloon's speed falls at a slower rate as the braking force is only being applied by (friction from the?) air pressure inside the car and is thus lower.
How did I do?
which way does the balloon move?
Relative to the road or the car? Are any windows or vents open?
jaffa cake isnt a direction!
No, it's more of a philosophy.
Forwards til it hits the airbag, then backwards and probably left and up a bit.
They move slightly forward and then back like most objects in the car.
Bollocks why am I answering.
jaffa cake isnt a direction!No, it's more of a philosophy
A way of life, surely?
The balloon dosnt move at all, but as the car slows it'll hit the windscreen
Maybe.....
is it wearing a seatbelt?
i can see the adverts now... "cougar knew his killer" *slow motion shot of balloon gently hitting the back of cougars headrest*
Relative to the road or the car? Are any windows or vents open?
Relative to the car, windows closed.
*snort*
Lots of images of small, sad-faced children with statically charged balloons stuck to their heads.
are you getting us to do your kids homework? Cheeky beggar.
are you getting us to do your kids homework?
Strangely enough, they haven't set him anything like that in reception yet. Maybe after half term?
Good point Phil. If he crashes, the balloon could hit him with the force of an inflatable baby elephant.
i dont allow inflatables in my car for this very reason, unless they're securely strapped down in the passenger seat. clunk click every trip!
it will stay in contact with the car roof at the same point?
Fabulous ! 😀phil/downshep combo
Good point Phil. If he crashes, the balloon could hit him with the force of an inflatable baby elephant
depends on the car?
[img] 
[/img]
Which direction is the car moving relative to the spin of the planet?
Forwards I think.
Balloon is travelling along at the same speed as the car.
Car slows by applying friction to the road.
Balloon has no such friction so carries on forward with just air resistance to slow it down.
No?
(I was always crap at relative motion so this may be completely wrong)
barely any momentum + lots of air resistance = nowhere much ??
(brackets omitted for opacity)
Dont forget the expansion rate of the Universe is decreasing.
It travels at a constant speed and direction until an unbalanced force acts upon it
I think balloon backwards. G force applies but it is floating - so all the air goes to the front and the helium to the back
G force applies but it is floating - so all the air goes to the front and the helium to the back
That explains why everyone in the back of the car passes out whenever I brake 😀
Theres a budgie hovering in a cage in an aeroplane hold going along runway thats also happens to be a conveyor belt. The belt stops suddenly, the plane accelerates forward. What happens to the budgie?
Does he get accelerated backwards through the grates on the cage and become budgie slices (think craft cheese slices) or does he continue to hover in his cage?
the budgie slams into the back of seat 34B and kills cougar and the STW joke threads are never the same again 🙁
Why does the balloon go up normally and rest against the roof? gravity . In the car you are applying a G force horizontally - so the balloon floats to the back of the car when you brake as the effective g on the space inside the car is no longer vertical.
TandemJeremy - Member
I think balloon backwards. G force applies but it is floating - so all the air goes to the front and the helium to the back
Anoyingly I agree with TJ.
But can you please use the word acceleration rather than G-forces?
The air moves foreward relative to the car, so the lighter baloon moves towards the back.
I think balloon backwards. G force applies but it is floating - so all the air goes to the front and the helium to the back
Ah, interesting, I knew there'd be a catch.
the budgie slams into the back of seat 34B and kills cougar and the STW joke threads are never the same again
Whether this is a bad thing or a good thing may be a matter of some debate.
Can budgies hover as such? I thought that was more a hummingbirds territory?
Was the cage in first class? Or cattle?
Just experimented on our youngest, with tragic results......
[img] 
[/img]
The budgie can hover as he is holding onto a helium baloon thats also in the cage. A vital point i failed to mention.
Aaaaaaargh that has just messed with my head.
(googled the answer)
downshep, i applaud your efforts to try and maintain a 'normal' life for your daughter, but being a man its evident you've chosen an odd pair of earrings, yes they're both ducks but if you look closely they're from different pairs.
Heliophile.
next time it could be a balloon's smiley face.
what about the kidnap victim in the boot btw?
The other ducks from each pair were bundled into a cage and conveyered to the airport.....
inertia.
C'mon aracer, don't keep us in suspenders
Are you expecting marks for your work?
i'd say backwards as well. assuming its full enough of air to float. interestingly, if you went round a roundabout quickly it should also move to the right of the car
ETA : unless the car was on a conveyer belt, in which case slowing the car's wheels wouldn't make any difference
On to the floor as I would have burst the stupid thing.
Is the question how does it move in relation to the world? or how does it move in relation to the slowing car?
As TJ says.
My friend got asked this in an Oxbridge entry exam many years ago. He said forwards and ended up going to Bristol.
Does it make any difference if you've sucked out the helium to make your voice go all funny?
Definitive answer...
Cool ta Milkie. Looks like TJ is right.
[smug mode]I'm always right[/smug mode]
This one is even better cos you can compare the balloons:
Not particularly related, but those vids made me think of this:
Now [u]that[/u] is responsible driving 😀
consider that the boiling point of Helium is (minus)268.93 (°C)
and then take in to consideration the figure 8.93(meters) being the world record distance a unicycle has travelled along the top of a beer bottle.
link: http://newslite.tv/2011/09/29/unicyclist-rides-along-a-row-o.html
remove without taking away, those figures, from each other and as if by magic, you have the answer to maths question of the day.
I hope that helps. (and no, I'm not about to tell you the answer to the boiling water question)
If you stand in the aisle of a train doing 100mph and jump, what happens then?
You fly through the air at 100mph and land exactly where you were before, still travelling at 100mph.
You fly through the air at 100mph and land exactly where you were before
How is that possible?
Because you were already travelling at 100mph before you took off.
You go straight up relative to the train, but you're flying at 100mph relative to the outside world. And you land straight back down again. Still going at 100mph.
so all the air goes to the front and the helium to the back
The car is full of air. How does the air go to the front?
Given that whilst sitting in a chair spodding you're already doing around 1000mph due to the rotation of the Earth, would you expect to be able to jump in the air and land in Ireland?
(For the purposes of this example, let's assume that you're not in Ireland already).
The car is full of air. How does the air go to the front?
because its heavier than the baloon, and, under braking, the axis of gravity pulls towards the front of the car. Same reason that the baloon rises when you let go of it
Given that whilst sitting in a chair spodding you're already doing around 1000mph due to the rotation of the Earth, would you expect to be able to jump in the air and land in Ireland?
But doesn't the earth rotate the other way, so you could jump from Ireland to the UK but not the other way round unless you started from the Atlantic.
But doesn't the earth rotate the other way, so you could jump from Ireland to the UK but not the other way round unless you started from the Atlantic
no.
x=mc4-speed of car x 22/7 divided by the circumference of the balloon - temperature inside of car. The answer is it bursts 🙄
Yes.. balloon moves backwards, cos the heavier air moves forwards and displaces the lighter balloon.
Imagine a container half full of water. You brake, the water moves forwards.. the air in the container moves backwards.
Tch, stay off the forum for one afternoon and I miss the perfect opportunity to be right and subsequently vindicated... took you lot almost a page for someone to get in there.
took you lot almost a page for someone to get in there.
and then it was TJ 😯
Because you were already travelling at 100mph before you took off.
Yes, but if you're going at 100mph, how can you land exactly where you were before?
Do you lot not understand the word 'relative'?
You're talking nonsense... you are talking about moving frames of reference (ie the train) but not specifying what you mean by 'where'.
[img] 
[/img]
Forwards, much the same as my mates dog did.
Dog asleep on parcel shelf.
Mate drives into the back of someone at lights.
Dog hits windscreen with tragic results. 😥
Balloon wouldn't move with pooch killing velocity as it has a large area that is subject to air resistance and a small mass. The dog had a small area and a large mass. Well, large enough to put a hole in the winscreen of a Ford Granada. The driver broke his thumb on the steering wheel.
up, its filled with helium innit.dont tell me i'm wrong, i've seen the film 'Up'
Phil is correct. The real question is why doesn't said driver add more balloons and float above the rest of the traffic?
Wait, is the car in the northern or southern hemisphere, and at what latitude? Is it travelling with or against the earth rotation? Are we ignoring the effects of charged ions? Is the car's headlining vinyl, velour, or something else. Do we know the coefficient of friction of the headlining? Is the vehicle on level ground? During braking, what attitude does the vehicle take due to weight transfer? Is the driver wearing a nylon jumper? Has anyone in the car eaten beans or radishes within the past 24 hrs?
Just polishing off my excel sheet, nearly there.
I think you'll need to account for the weight of the balloon too TuckerUK.
The contents may be lighter than air, but the foil/rubber of the balloon, plus possibly string and maybe lettering or a little party tag all need to be accounted for as the inertia throwing it forward must be overcome by the air "pushing" it back. 🙂