I know its a stupid question, but its been BUGGING me for about 6 years?

Question

Ive always wanted to know, if a fly was like, in a car, does it have to work really hard to keep up with the speed of the car or does it just hover like it was in a stationary room. I used to think that it would have to work really hard because the car is moving really fast, and we dont work hard because we are sitting down on seats. I hope it can be solved!?

Answer 1

i know little about physics, but I'm guessing it has to do with wind resistance. There is no more wind resistance in the car then there would be in a normal room so the fly doesn't notice a difference. But...if you roll the window down, you've brought in a little resistance and also you'll notice if the fly goes out the window he doesn't keep up with the car, he is blown far behind you...

If he had to struggle to fly then the same principal would hold for walking on an RV when its moving, or even on an airplane...we are shielded from the wind resistance

Answer 2

the first answer was correct, to my understanding.
Imagine the fly needs a rest, so it sits on the dashboard, or the mirror. It is now a part of the cars body, more or less, and hence is travelling at the same speed as the car. So it already posseses kinetic energy, just like everyone in the car (a collision will fling anyone without a seatbelt out the window) this energy solves the problem of the fly having to work extra hard to build up extra speed.
If the car is accelerating/decelerating then the answer to your question is yes, but if we assume constant velocity, then the fly also has that velocity and will not have to work any harder than if it was in a still room ( we also have to assume that windows are up, so that air pressure remains constant too....)
just thought id add that to be annoyingly original.

Answer 3

If you're in an airplane and jump do you slam against the back wall? I don't haha.

The fly, in the car, does not need to work any harder inside the car to fly despite the car traveling at a far greater speed than the fly is even capable of. Like the above stated, the fly is already traveling at the same velocity with the car and therefore will experience a feeling of non-motion, because relative to the car, the fly isn't moving. Relative to the earth, the fly is traveling at an insane rate but won't feel the effects there of.

In other words, If I'm running down the street right now, I don't feel the effects of Earth moving through space because I'm traveling with the Earth at the same velocity.

edit: Wind resistance is not a factor at all, by the way.

Answer 4

Well,in theory the fly has to do extra work provided the car is not absolute air tight because the fly does not experience any force from the car ( It is not in contact with anything) and so the energy required for the motion is being provided by the fly itself and not by any work done by the car due to the absence of any force. But, in practice the fly won't have to do any work because the air currents present in the car due to its motion will carry it along(due to the small mass of the fly). If it were a very heavy thing , say a bird, then the bird would would have to do work to keep up with the car. So far as a person sitting in a car or an aeroplane is concerned, he does not have to spend any energy because work is being continuosly done on him by the normal reaction of the seat and floor.

Answer 5

If the car is accelerating or decelerating then the fly will have to work to stay in the air. More likely it will hit some surface in the car and let it give it the push it needs to get up to speed. Once the fly and car (and air in the car) are moving at a constant speed then the fly won't have to work any harder than it would in a stationary car.

A car moving at a constant speed is an "inertial reference frame", as described by Albert Einstein in his special theory of relativity: some great minds have thought hard about this kind of problem.

Answer 6

Since the air in the car is moving at the same rate as the car the fly is carried along without any extra work. If the windows are open in the car the outside air is going to be mixed with the inside air and effect the fly's ability to fly.

Answer 7

If the car is moving at a steady speed the fly does not even know his flying, the same as the kids can throw a ball around in the car same as when its standing. Only when the car accelerate or brake does the fly move backward or forwards if it is in a hover.

Answer 8

There is a differrence between the motion of a car a rocketship.
The car scenario motion is as follows;
Power is given to the car to make its move including all its mass contents. The car during its motion experience two forces ,which are the friction force of the road and that of the gravity field.So the power of motion must do work against those forces. The car has enough power to move a certain car lenght. After that more gas is needed to make it move another car lenght ,and so on.Therefore to increase the speed of the car additional power must be added.

The rockets hip scenario is similar to the car. The difference is that afer power is given to make the ship move in space ,no additional power is needed to make it move because there is no road friction forces that contributes to power loss. The ship willl move at that velocity forever in space unless additional power is given to increase its velocity.(see Newton's first law of motion(Law of Inertia).

Power of motion / volume of space displaced = Density of vehicle x velocity ^2 / Time

Note; if you are in a car which is moving in the dark you dont see yourself moving. Its called Galileo Principle of Relativity.

In the case of a fly moving inside the car ,it would not work any harder than if it was flying normally outdoors.. The reasons is that the air inside the car is part of the mass of the car as it moves with the car.So to the fly, the air appears stationary.
Hoe this solves your dilemma.

Answer 9

Lindbergh when crossing the Atlantic struggled with a similar problem- How much extra fuel was the fly in his cockpit going to cost him. It kept him awake, which I hope is not happening to you.
A fly inside of a car has a flight speed relative to the enclosed space and therefore has to only expend the energy require to maintain that thrust (once equilibrium is achieved after any acceleration).

Answer 10

as long as you are contained within a system like your car, and this system is moving at a constant sped all laws of physics will work as if the system eas standing still. if you accelerate both you and the fly will be affected by a force but as long as the velocity is constant everything inside the car will behave as if the car was stationary.