FORUMula1.com - F1 Forum

[racechick]

I need a technical answer to this question. Someone very special to me asks, and Im not good at these questions.
Here is the question..
" Why, if there is a fly in the car, doesn't it just hit the back window becasue surly it can't fly as fast as the car.."

My answer was, well why dont we hit the back window ? we cant run as fast as cars?
So come on technical guru's what's the answer?

[LewEngBridewell]

It's a bit like the whole thing of "why, when you jump up on a train, do you not end up landing further down the carriage?"

The explanation is probably really obvious and simple, but I'm too tired to think about it now

[racechick]

Yep, I can see you and I are on the same wavelength on this!!!

[acosmichippo]

Everything in the car is moving at the same speed, so each object relative to another will appear motionless. Only changes in velocity (acceleration) are perceivable. You can bet that if you slammed on the brakes or opened the window, that fly would have problems.

So no, a fly cannot fly at the same speed as the car, but it doesn't have to.

[racechick]

Yes. I can sort of follow that line of thought.........just. I'll pass that on. Thanks.

[acosmichippo]

I guess another way to think about it would be from the air's perspective. To you, the air in the car feels motionless. But if you stick your hand out the window, you feel the outside air rushing by at 60mph (for example). It's the same for the fly. The fly in the car is motionless, but flies outside splat up against the windshield.

[racechick]

YES! Its becoming clearer by the minute. I think I get it. In the car you're like in a little cocoon and you dont get bothered by things outside. Thats clear, I get that. But why then do people get travel sick? And why do pilots have to wear Gsuits when they go really fast? And why was JPM sick in a jet?

[scotty]

Momentum.

People get travel sick because of moving up and down, i think.

[acosmichippo]

Motion sickness is psychological. I think it has something to do with people's brain having trouble reconciling that they're moving when they don't feel like they are. I've never had a problem with it, so I can't really say.

Pilots wear G-suits because of extreme changes in direction/speed (acceleration). For example, you know when an F1 driver takes a long turn at 150+mph, their necks feel strain from their 8-pound head wanting to continue on its path in a straight line. Just like a driver's head, their insides (organs, blood, etc) are susceptible to the G-Forces as well. Multiply that by a few times (as in the case of a fighter pilot), and the human body needs assistance to cope with the forces and keep everything in place.

In short, F1 drivers and fighter pilots are perfectly comfortable when driving/flying at constant speeds and direction. It's only when they accelerate that they experience G-forces.

[racechick]

Momentum.

People get travel sick because of moving up and down, i think.

I thought it was to do with your eyes seeing things going at a different speed to your body feeling them? Still not sure how that fits in with the fly though?

[scotty]

Momentum.

People get travel sick because of moving up and down, i think.

I thought it was to do with your eyes seeing things going at a different speed to your body feeling them? Still not sure how that fits in with the fly though?

I dunno how it fits in with the fly but you asked I mean, people get travel sick on boats and planes, where you can't always see things moving past...

[racechick]

Motion sickness is psychological. I think it has something to do with people's brain having trouble reconciling that they're moving when they don't feel like they are. I've never had a problem with it, so I can't really say.

Pilots wear G-suits because of extreme changes in direction (acceleration). For example, you know when an F1 driver takes a long turn at 150+mph, their necks feel strain from their 8-pound head wanting to continue on its path in a straight line. Just like a driver's head, their insides (organs, blood, etc) are susceptible to the G-Forces as well. Multiply that by a few times (as in the case of a fighter pilot), and the human body needs assistance to cope with the forces and keep everything in place.

In short, F1 drivers and fighter pilots are perfectly comfortable when driving/flying at constant speeds and direction. It's only when they accelerate that they experience G-forces.

So if a car accelerated fast....then would the fly go shooting towards the back window?

[racechick]

Momentum.

People get travel sick because of moving up and down, i think.

I thought it was to do with your eyes seeing things going at a different speed to your body feeling them? Still not sure how that fits in with the fly though?

I dunno how it fits in with the fly but you asked I mean, people get travel sick on boats and planes, where you can't always see things moving past...

Im not even sue if it does fit in with the fly The thought just crossed my mind, that there might be a connection.

[acosmichippo]

So if a car accelerated fast....then would the fly go shooting towards the back window?

yup.

I'm not very familiar with motion sickness, but I think it has more to do with conflicting sensory input than actual changes in speed or anything. Meaning, some people's brains, for some reason, have trouble coping with the fact that their eyes are telling them one thing, and their inner ear or sense of motion is telling them something else.

[stonemonkey]

It's the movement of the air inside the car that causes the fly to accelerate with the car, say you have a flat surface inside the car with a bowling ball on it, when the car accelerates the ball will tend to stay motionless with respect to the ground and shoot to the back of the car, the same thing happens with the fly, it's inertia will try to keep it motionless with respect to the ground, but because of it's high air resistance/mass (compared to the bowling ball) the air resistance will accelerate the fly forward.

You accelerate with the car because of the force exerted by the seat on your body, the fly is accelerated by the force exerted on it by the air inside the car.