Discussion in 'General Discussion' started by PaulStat, 9 Mar 2006.

1. PaulStat

# Location: Cotham, Bristol

Ok so a fly is in flight in a car that is travelling at 80mph, since the fly isn't actually touching the car as such. Does it have to fly 80mph in the same direction to avoid being splatted against the back window?

2. Clarkey

# Posts: 18,145

the back window? It owuld be splattered on the front window before it made it to the back, no way a fly can go 80mph lol.

3. spirit

# Posts: 1,885

man loads of people with these q's today, thinking thursday!

Last edited: 9 Mar 2006
4. Raikiri

# Location: Brighton

The fly is already in the car before it starts travelling...

My answer is a question, do you run at 80mph when in a car?

5. Gilly

# Location: I'm back baby!

:/

Does the air inside the car move at 80mph to avoid being left behind?

No it does not.

Do you have to move at 80mph to keep up with the car?

No you do not.

Whats with all the inane questions these days?

6. PaulStat

# Location: Cotham, Bristol

which ever window it is, but you see my point?

7. Sic

# Location: SO16

i started reading this and thought "what's with all the questions about speed and whatnot?!" but it's actually a fun question. and why would it fly into the front? if a car was moving forward at 80mph and a fly was hovering then it'd get hit by the back window, surely?

no, but because you're sat on the seat, you're being pulled along by the car, so the car is making you move 80mph. if you were floating in the car and it started moving, i'm fairly sure you'd go through the back window. unfortunately, i cant recreate this to prove it.

8. ChroniC

# Posts: 9,356

if it started in the car then no, its called enersure (i dont know how to spell it though, thats called being thick )

9. Sic

inertia?

# Posts: 6,720

thats like saying when your in a plane thats at exactly the speed of sound in flight, if you get up and walk from one end to the other, have you personally just gone fast then the speed of sound

11. ChroniC

# Posts: 9,356

thats the one, thanks see hes smart

# Location: Frimley, Surrey or 38,000ft

you've just got to remember that all speed is relative. In a car, all of its contents are moving at 0mph relative to the car, but the car is moving 80mph relative to the road. So the fly will be flying at its normal speed, but relative to the road it will be its relative speed to the car + cars speed to the road.

13. SaBBz

# Location: Elsewhere

It's all to do with the frame of reference

14. Rich_L

# Location: Santa Barbara, Californee

Hmmm.

I reckon while the car was accelerating the fly would have to match the cars acceleration to stay in one place, but once the car was travelling at a steady pace it could fly around as normal. Alternatively it could land and let the car body accelerate it instead!

Think about if you are throwing a tennis ball in the air in a car - if the car accelerates while the ball is in the air the ball moves to the back of the car. Likewise if the car brakes suddenly when the ball is in the air it moves to the front.

Could be totally wrong though

15. Enfield

# Location: Hampshire

what a dumbass question lol

16. PaulStat

# Location: Cotham, Bristol

I knew there was a reason why this couldn't be the case, but couldn't for the life of me think why, anyway thankyou for clearing that up

17. Gilly

# Location: I'm back baby!

When an astronaut is floating in his shuttle in space is he having to hold on to stop himself being propelled through the back wall?

18. Scuzi

# Location: Екатеринбург

If the car set off from a standstill and the fly was hovering in the car, it would get splatted on the back windscreen. Even though the fly is 'inside' the car, it is not connected to it therefore is hovering in a constant position in space. The speed of the air has nothing to do with it as I flys wings do not rely on airspeed to fly.

So the fly is hovering inside the car, what if you removed the roof? The fly is outside the car. Forget about airspeeds and whatnot as it is technically irrelevant.

Read up on the conservation of momentum and inertia principles.

19. Ricochet J

# Posts: 12,904

Well yeh it's inertia. If you had all the windows open then perhaps the fly would have to keep up with the car's speed.
If you think that its already travelling at 80mph default, then any speed ontop of that would be the ms-². Which we all know is accelaration (Change in velocity over the time taken for change)

20. Visage

# Posts: 10,708

Nope - you're right.

In fact, its a derivation of this (but with light beams) that gives one of the simplest derivations of time dilation in special relativity.