A question about Relativity? If a mosquito is flying in the inside of a car why doesnt it go to the back of it

Question

Of course I know it is because there is nothing making it go back given that there is no wind and indeed the mosquito is flying relative to the cars velocity. Nevertheless when a person is travelling in a really fast car why do we tend to get sucked into the seat, I mean I know it is because of inertia, but still why doesnt the same principle apply to the mosquito and make it go to the back of the car?

Answer 1

The only time you get sucked back into the seat is when the velocity of the car is changing. If you remain going in a straight direction without increasing or decreasing your speed, the only sucking would be on your butt by the force of gravity, which is also known as your weight.

It's acceleration (change in direction, speed, or both) that sucks you into the back of the seat. This results from f = ma; where f is the force that pushes you (not really sucks you) on your back by the seat back, a is the acceleration from the speed and/or direction change, and m is your mass. You're being pushed by the seat back because F is always acting in the direction of the acceleration. And when accelerating, the direction is forward, toward the front of the car; so that's the direction of F.

What you feel on your back, when accelerating, is the equal and opposite force of your body pushing into the seat back. We know there is one because you are stationary relative to the seat back as the car accelerates. So the net force on your body is f = (P - R) = 0 = ma; so that P, the push by the seat back, equals R, the reaction force by your body. In which case a = 0 and you are not accelerating relative to the seat back.

In the case of the mosquito, gravity is sucking on its butt, too. But it offsets that pull by lift force from its beating wings. And so long as there is no acceleration of the car, the mosquito will be content to believe his tiny world around him is stationary because there are no forces other than gravity acting on him.

Answer 2

Yeah, i believe the same thing happens to the mosquito, it will get sucked back. But i think at the small scale of mosquito the air has much more of an effect on the mosquito as it does on you. In other words the mosquito adjust to the change in velocity much more efficiently than you can because the air is a great source of friction and stability for it.

As a thought experiment lets increase the mosquito's size, lets say he is the size of a full grown cat ..lol. Now its easier to imagine i think that the inertia that that thing feels is enough to send it back. The mosquito would have to produce much greater lift to keep him steady then if it weighted an once.

Last thought experiment, if there were no air, and you just hung the mosquito from a string (neglecting the string weight) that mosquito would experience the exact same momentum backwards as you would.

Answer 3

The mosquito will bounce around if you make turns or stop and go. The problem might be that if you're driving you're not really looking that close at the mosquito's movements.

Also, the inertia doesn't last forever. It only lasts until the car stops accelerating. You'll notice a push every time the car changes gears, but when you hit a constant speed, you should be able to get back up.

Answer 4

eyeonth ... is correct. You have to consider gravity and acceleration effect upon mass. When you are in your car and driving down the road, acceleration and gravities affect is upon you plus the car, a single unit of mass. The mosquito, on the other hand, is but a very tiny mass both relative to you, the car, and the earth. It feels proportionally the same gravitational and acceleration effects but only slight so.

In fact, because of its tiny mass, relatively speaking, the degree of acceleration and/or deceleration upon the mosquito is so small that you would not be able to observe it directly.

Answer 5

The feeling you're talking about is the acceleration, not the velocity.