Why is it that when a car is moving and there is a bug flying around in the car, that the bug is fine? Shouldn't it hit the back of the vehicle as soon as the car starts driving?
2007-07-23 07:48:38 · 18 answers · asked by Amanda 2 in Science & Mathematics ➔ Physics
The bug is flying in the air and the air in the car is moving along with the car at the same rate. If you were in a convertible, the fly would be blown away.
The fly is flying at normal fly speeds (3-5 mph) relative to the air in the car, but relative to the ground, it is traveling at the rate of the car plus or minus that speed.
Hope that helps.
2007-07-23 07:52:25 · answer #1 · answered by Grendle 6 · 3⤊ 1⤋
The bug flies in the air.
The air moves forward just as fast as the car.
Although there are pressure gradient transients created within the car as the car accellerates and decellerates, these changes are apparently not so great as to disrupt the bug's flight pattern significantly.
You can see the effect of pressure gradient transients in a car if you have helium balloons in the car. 1. Place a helium balloon in the middle of a stopped car. 2. Accellerate the car and start driving forward. 3. You will observe the balloon - seemingly paradoxically - move forward in the car. How can this be, you ask? Since everything else seems to be thrown to the back of the car as the car accellerates? The answer to that question is that the AIR in the car is pushed to the back of the car - and since the AIR is denser than the helium - the helium gets pushed forward in the car by the denser air that forms a zone of higher pressure at the back of the car during accelleration. The opposite will happen when you stop the car.
So, a bug in flight in a car will be subject to the same sorts of air movement. However, at the normal accelleration and decelleration rates of most passenger cars, the bugs use their innate flying abilities to fly, seemingly unaffected - not unlike how the bugs fly outside in mild breezes without too much problem.
So, the short answer is - the bugs fly because the air moves with the car and pushes them forward with the car. In a vacuum - the bug would seem to go backward as the car accellerated - but of course, in a vacuum, a bug could not fly.
2007-07-23 08:08:28 · answer #2 · answered by Anonymous · 0⤊ 0⤋
The air inside is not subjected to the speed of the vehicle, if there was no windshield then it would be 'pushed' back or rather left in place as the car moved forward. So without the effects of the outside world you have a sort of 'vacuum' in the car for air currents and the bug is unaffected, with windows open there exists turbulence but not uniformly throughout the car so it can still fly around. If it ventures too close to an open window it can escape or get sucked/pulled out at the right speed.
2007-07-23 07:53:26 · answer #3 · answered by John96 4 · 0⤊ 0⤋
Not at all.
The bug is traveling in the same frame of reference as the people in the car. But he bug has very little mass unlike the people in the car. When the car begins to move the air moves too and carries the bug along. There is very little outside force acting on the bug as it flies around except for the action/reaction forces from the bugs wings pushing against the air in the car and the air molecules (air resistance) pushing back on the bug's wings enabling it to fly (except of course when a window is opened and wind rushes in and blows the bug all over the place.). If you could put the bug in a rocket with no air molecules and imagine it surviving, it would get pushed to the back to the rear of the rocket. In fact a dead bug on the back windowsill of the car might even roll around as the car turns.
The people on the other hand have a lot of mass, so there are larger forces acting on them and they can feel them when the car speeds up or brakes, or turns corners.
The small bug would feel it but not anywhere near as much.
2007-07-23 08:06:16 · answer #4 · answered by Anonymous · 0⤊ 1⤋
Most of the answers kind of miss the point. The air that the bug flies in is moving at the same rate as the car, whether still, accelerating, or moving at a steady pace.
The inertia during acceleration and the momentum when the car brakes acts more strongly on objects of greater mass. The air has little mass, and the bug, not much more than the air, compared to the mass of a human body.
2007-07-23 07:59:52 · answer #5 · answered by Vince M 7 · 0⤊ 3⤋
Sadly I have sometimes wonder this myself, I think maybe because there is no wind so the bug can fly with the car or land on a window if the car is going to fast. They had a similar question on Mythbusters where a truck driver who caried birds would bang on the truck so the birds would fly and his load would therefore be lighter... I forget the outcome...
2007-07-23 07:55:58 · answer #6 · answered by Anonymous · 0⤊ 1⤋
Most people have troubles understanding this concept, but it's quite simple. You have to imagine that air has mass (which it does). Now use Newtons 1st law... Objects in motion (at constant velocity) that have mass, will stay in motion (at the same velocity) unless a force is acted upon them. So now while the car is moving at constant speed, the air inside the car is moving at the same speed. The relative environment to the fly, or to anyone else inside the car would seem the same as if they were outside, except for no wind (which creates force).
2007-07-23 08:02:13 · answer #7 · answered by Ilya S 3 · 0⤊ 2⤋
Why would it hit the back of the vehicle? There is no force acting on the bug. It's very light, there is a small amount of intertia that pulls on it, but once the car reaches uniform velocity, no extra force is applied to the bug.
2007-07-23 07:52:47 · answer #8 · answered by Pfo 7 · 0⤊ 2⤋
The air in the car is contained and it moves with the car. The bug is displacing this same air when flying.
2007-07-23 07:52:01 · answer #9 · answered by Anonymous · 2⤊ 1⤋
No particular frame of reference is special.
In relativity, any reference frame moving with uniform motion will observe the same laws of physics.
The frame of reference inside the car pertains to the life in the car, the same as people outside the car on our planet which is moving also are in a different frame of reference.
2007-07-23 09:15:30 · answer #10 · answered by MichelleMcD81 2 · 0⤊ 1⤋