If a Housefly is in a Car...?

Question

And it starts flying towards the front at 80 MPH (129 KPH) and you suddenly slam on the brakes, would the fly smash into the window? Provided it's a hardtop with all the windows up.

Answer 1

Only if you suddenly stopped, and the fly was atleast a few centimeters away from the glass..

I wouldnt want to be in a car with you if drove 129 KPH ....... Meh..  

Answer 2

.This question has been asked in different forms for years. The most important thing to remember concerning this, and other questions like this, is that there is no way you can differentiate between an environment at rest, (whatever that is) and one which is in a state of constant motion,i.e. not accelerating. The fly., the car, the people, and everything in the car are all traveling at 80 mph. As far as the laws of mechanics go, that's the same thing as if they are at rest. If there were no windows and you were to try to determine whether you were moving or not from inside the car, there is no test you could perform to prove you were moving or not. When you slow down, you're in an accelerated frame of reference and you and everything in the car would try to keep moving in a straight line at 80 mph. That's why you wear seat belts. Unfortunately, the fly wouldn't be wearing a seat belt so it would be propelled toward the front of the car at 80 mph. By the way, the velocity of the fly would affect the speed with which it hit the windshield. If it were flying backwards,(towards the rear of the car at 20mph), it would be traveling towards the windshield at 60 mph; similarly, if it were traveling towards the front at 20 mph, it's speed would be 100 mph.

Answer 3

No it wont, 80mph is the speed of the car, the fly's immediate surrounding is the car, with which the speed is measured, so the fly will stay still as it has no inertia, no physical contact with the car.

Answer 4

No more than you would smash into the front. Friction slows you down by the seat of your pants, plus the seatbelt. The air will slow the fly down. Try it with a balloon next time you are a passenger in the back. The ballon does not smash into the front. The air will move forward and create a bigger pressure at the front which will slow the fly down.  The air will slow down with the car and the fly is flying through the slowing down air. Good question.

Answer 5

yes, because of the g-force. But only if you stopped very very quickly, usually it's hard to stop that quickly in a car though.

Answer 6

No.

Its all about kinetic energy. The fly is not producing any kinetic energy itself so there is no inertia.

Answer 7

You'll smack into the window.

The fly isn't doing anything, it's just hanging there. So it's not going to smack into the window.  

Answer 8

a fly cant fly 80 mph

Answer 9

the fly would smash

Answer 10

Yes, the fly would slam into the window because the fly is also moving at 80mph with the car.  He's then moving at 80+flyspeed mph towards the window.  The car and everything attached to the car is then moving at 80+deceleration.

The fly would hit the window at a speed of -deceleration+flyspeed  

Answer 11

Yes, the fly would smash the windshield if the car stopped near instantaneously. It has enough mass to cut through the surrounding air and hit that windshield. If it had a large surface area and low mass, like a whisp of paper, then the surrounding air can create enough drag to slow it down.

A similar example is to have a light balloon hanging from a rope in a cart. Then roll the cart down the hill and have it hit a tree - you will see that the baloon swing forward slowly. If it had a smaller surface area and more mass the the balloon would have rocketed forward snapping the string taut.

Hope that helps