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This is a situation based question and I don't know whether is it directly connected to physics or not. Sorry, if not, I thought that it would be best to ask it here, of it has some interesting application.

Anyways, I recently started to learn Newtonian mechanics as a high school student and recently learnt about laws of motion.

Now consider this situation which I have encountered many times. The situation is that I'm inside car and car is moving, window are open and suddenly a fly enters the car and it is pretty comfortable inside (making us disturbed). Now I wonder how the bee is managing inside the car. What I mean here is that we are having a velocity because we are in contact with car(as we are seated on the seat and not flying) whereas the bee is apparently, not in contact with car and hence should not possess the velocity of car ( I deliberately said that windows are open, because may be closing of windows affect the motion of bee, which I neither know nor experienced), but the bee is flying here and there annd this according to road frame must have a velocity greater than car, which is of course not the case ( I searched speed of a bee on browser and found it to be around 10-15 miles per hour, which is way less than speed of car, I am in.

So what's the reason for this result. May be it's biological, which I don't think and I considered this situation from physics's viewpoint, with conditions idealized. So according to me the bee should be thrown back to the end of car, because there is no considerable friction and as per the law of inertia. Other thing which I considered was pressure, which I came to conclusion can surely not change as windows are open. I'm not able to go beyond.

May be the question seems stupid, but the real aim of physics is understanding real situations and not completely idealized ones. So, I would appreciate any help on how to analyse this situation and to know what is going on from a physicist point of view.

EDIT In the other question, the conditions are different from mine. There windows are closed and here open, which may make a difference, I suppose. Also I didn't found a satisfactory answer there, so I posted it on the basis of my common experience.

Thanks a lot.

Abhinav Dhawan
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  • @Diracology I referred to that but couldn't get an answer there. Also it seems that conditions are not the same in both the questions. – Abhinav Dhawan Jul 25 '17 at 13:14
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    Note that the velocity of a flying insect (or most things flying in air) is relative to the air around them. Thus if a fly is surrounded by air that is hurtling down a highway at 120km/h (because it's inside a car), then the fly itself is also hurtling down the highway at a comparable speed. – Arthur Jul 25 '17 at 13:24
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    @AbhinavDhawan It definitely is explained a bit there (particularly the second answer). Most of the air in your car is moving with the car. There are some quick streams coming from the window; but those die out on the inside. – JMac Jul 25 '17 at 13:24

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The bee flies in air.

Outside, the air is often still, which means it has the same speed as the ground. The bee flies at 10 - 15 mph through the air, which means 10 - 15 mph with respect to the ground.

The car contains air and carries that air with it. The air has the speed of the car. The bee flies at 10 - 15 mph through the air, which means 10 - 15 mph with respect to the car. If the bee flies forward, it moves over the ground faster than the car. If it flies backward, it moves over the ground slower than the car.

Suppose a wind is blowing and the car drives just as fast as the wind. The bee could do the same thing outside the car as inside.

mmesser314
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  • Thanks for your answer . You said that air has a speed of car... Now is this due to relative collisions of air particles, which make them collectively move with the speed of car? – Abhinav Dhawan Jul 25 '17 at 13:47
  • Yes. Air molecules next to the car bump into the car. These bump into molecules nearby. And so on. – mmesser314 Jul 25 '17 at 13:51