Sciencey type question that bugs me

[rurallib]

Dear Mr. Science,
Say I get in my car and there is a fly in the car.
said fly starts flying as I start my car and put it in gear.
I crank right up to 55 MPH ( I live on a highway) and the fly is still flying in the air in the car.
Why did the fly not slam into the walls or windows of the car as it accelerated? The fly is not strapped to the car but in the air.
Corollary - how does that damned thing not get sucked out when I roll the windows down?

Thank you,
wishing that little sonofabitch would die in Iowa

[Orsino]

1. The fly is cushioned by air...

...and isn't massive enough to have a lot of momentum. The air in the car wouldn't stop you, or even slow you down significantly, but it saves the fly.

It can be sucked out when you roll down the window, too, but not much air has to leave the car to equalize the pressure, so unless the fly is right there next to the window, it's staying aboard.

[rurallib]

3. So it is like the fly has its own moving compartment of air?

I don't know why I am having a hard time picturing this but I think I get it.

[Mefistofeles]

6. It's ok not to understand science

I still can't figure out what was there before the Big Bang, other than nothing. And nobody has been able to explain to me how "nothing" can explode.

[uncommon]

12. Understanding scientific theories of the "beginning" of the universe requires

an ability to accept that there is science we don't know or understand yet, but from what we do know there is every possibility of a big bang.

[Deep13]

18. It really isn't.

This is ordinary, everyday mechanical physics and is easily understandable once explained.

[uncommon]

19. I concur.

A basic understanding of science cures a LOT of ignorance.

[uncommon]

10. The fly is floating in the air,

and the air doesn't rush back when you accelerate unless you do so extremely quickly and even then the windows would have to be open for significant air movement. A fly can fly in 10 mph winds, so at the rate most normal cars accelerate for normal driving, there would be minimal impact.

[Rabrrrrrr]

11. Not momentum, but inertia. These are utterly different concepts.

[Orsino]

15. Both momentum and interia.

Though momentum is indeed more relevant to the question of whether the fly could crack your rear window. x(

[Mefistofeles]

2. Similar question: Why isn't the car moving at 1000 mph? (Earth's rotation speed)

And why isn't the fly spinning as well.

[rug]

4. 1) It was made by Hyundai.

2) It is not a spider.

[uncommon]

13. Gravity darling.

Because of our natural attachment to the surface of the planet, its movements are our movements. Like being in a car.

[Dr Morbius]

14. The car IS moving at over 900 mph. But so is the road and the fly.

Figure out sometime the speed of the earth traveling in a rough circle about the sun with a radius of 93 million miles in 365.25 days.

[Kaleva]

5. The air in the car doesn't get stuck to the rear window.

As the micro-atmosphere within the car travels along with the car, the fly happily flies around in a static airspace.

[elleng]

7. Aha, 'micro-atmosphere!'

[struggle4progress]

9. Are you sure? Cuz there's all this goo on my rear window

and I'd been telling myself it was just some air that got stuck there during some of my rubber-burning accelerations

[elleng]

8. Somehow, I KNEW this was going to be your question!

[HiFructosePronSyrup]

16. Because your car's alternator is essentially a large solenoid. In other words, a magnet (a gauss)

[realisticphish]

17. hahaha

[gratuitous]

20. Now, I'm on a one-mile test track

I'm going to run two laps. But I get stuck in second gear on the first lap, and only go 30 mph. How fast do I have to go on the second lap to average 60 mph for the two laps?

Note: The fly is still in the car.

[Gidney N Cloyd]

21. This should explain things:

http://www.youtube.com/watch?v=44DlSj6bnn4