when a fly comes through a car window after being quite still, why doesn't it fly to the back of the car?

Question

do you know what I mean? so a fly has been pondering about and it drifts into a window of a fast moving car, why doesn't it go splat on the back window....

ok ok so the car isn't moving so fast. what happens if the car is a convertable??

p.s. I spelt 'convertable' wrong, it should be spelt convertible.

Answer 1

as soon as the fly enters the car the fly does not fly to the back because the air inside the car is effectively still so it is just like a fly flying around a room

Answer 2

Once inside the car, the fly is in a new atmosphere--that of the automobile. There the air is still, and the fly is able to navigate as if the car was not moving. If you open the window, though, the fly could get caught in the turbulence between the still inner atmosphere and the rapidly passing outside atmosphere (assuming the car is moving). The fly could be swept out in this turbulence. Poor fly!

PS: a fly will NEVER drift into a side window of an automobile while it is moving at a high rate of speed.

Answer 3

How does a fly that is at rest fly into a car moving at 30 mph. Think about your question - it answers itself.

A fly that manages to get through the window of the car must be moving at the same speed as the car.

OK so what about flies coming in sideways on. Well, if they miss the window and hit the windshield - splat. If they fly towards the window the boundary layer of air travelling along with the car will drag them up to its speed.

Answer 4

yes

well, maybe.

Let the fly blow in near the front of the vehicles cab. The fly is initially at rest and suddenly finds itself in a moving car. The air inside the car is moving with the car, say at 30 mph.

Initially the fly is at rest with respect to the outside world, but inside the car it is initially moving toward the back of the car at 30 mph, so it suddenly experiences 30 mph wind blowing toward the front of the car. Since the fly has mass, and therefore momentum, it cannot be accelerated to 30 mph instantaneously. It depends on the surface area to mass ratio.

As the fly is accelerated toward the front of the car, it is still moving toward the back, but its velocity toward the back is slowing as it accelerates toward the front by the apparent wind inside the car as seen by the fly. Eventually, it reaches its settling or steady state speed of 30 mph (same as the car), but it needs a certain distance to do it. The question is whether the 6 ft of interior space is enough.

For a fly with a high surface area to mass ratio, it may be accelerated to 30 mph within the 6 ft confines of the car. Certainly a mosquito would not hit the back window, but a fly might.

At 80 mph, even a fly certainly would hit that window.

As for how this could happen, well its a fictitious scenario concocted to aid learning the laws of motion. But beyond that, there could be a cross wind that brought it in, or the fly could actually be moving slightly, or the air currents around the vehicle whipped it in or any number of other reasons.

Basically you are trying to learn the laws of motion, so the important facts here are mass, momentum, velocity, direction, time and possibly air resistance.

Understand, that acceleration can be in one direction, but velocity can be in the opposite direction.

Answer 5

Amazing feat! A pondering fly drifts into a fast moving car.. it's more likely to go splat on the car window before it gets in the car..

Answer 6

Once it is in the car, the air in the car is moving with the car, so the fly is now traveling with the car.

Answer 7

Awesome question - have you ever seen a pegeon walk backwards??

Answer 8

very interesting question i cant answer it but wicked question lol x

Answer 9

my dear, she is also free to do what she likes