# Inertia humming bird is hovering in a car

#### socialcoma

if a humming bird is hovering in a car going at a constant rate, and the car comes to a sudden stop, will the bird fly into the windsheild?

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#### check

Yes! I think... :p

Interesting side note:

If you had a helium filled balloon in your car and attached it to the floor, when you hit the brakes it will actually go BACKWARDS. If you accelerate, it moves forwards, etc. The movement of the balloon is the opposite of what you would expect. This is due to the movement or air and air density in the car.

#### dav2008

Gold Member
Ok..well for the humming bird...when it is floating, it is staying in place in the "bubble" of air in the car...when the car brakes, in order for the hummingbird to hit the windshield, all that air would have to be smashed forward...which would leave a vaccuum in the back and then that would be filled up...so wouldnt it get really windy in the car whenever u stop?(assuming that this is all with the windows closed)

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#### socialcoma

yes, all of this with the window closed

#### russ_watters

Mentor
Re: inertia

Originally posted by socialcoma
if a humming bird is hovering in a car going at a constant rate, and the car comes to a sudden stop, will the bird fly into the windsheild?
Do *YOU* fly toward the windshield when the car suddenly stops? (hint: why are you wearning a seatbelt?) There's your answer.

when it is floating, it is staying in place in the "bubble" of air in the car...when the car brakes, in order for the hummingbird to hit the windshield, all that air would have to be smashed forward...which would leave a vaccuum in the back and then that would be filled up...so wouldnt it get really windy in the car whenever u stop?
The hummingbird isn't floating - its FLYING. Huge difference.

#### check

LOL. I think we're making this question tougher than it is.

#### LURCH

Re: inertia

Originally posted by socialcoma
if a humming bird is hovering in a car going at a constant rate, and the car comes to a sudden stop, will the bird fly into the windsheild?
I think not. Like the hellium balloon, the humming bird rides the air within the vehicle. Admittedly, the humming bird is less bouyant than the balloon, but it is also far less massive than a person. Additionally, the bird is not a passive passenger of the air currents, like the balloon. On the contrary, it beats its wings something on the order of 20-30 times per second. This gives it many opportunities for "course correction". I don't know what their exact manuevering specs are, but I've seen them pull some serious G's.

So, although the bird might tend to "LURCH forward" a bit, I doubt you could get it to hit the windscreen simply by breaking. Maybe by crashing the car into a wall or something.

#### socialcoma

i dont mean will the bird actually hit the windsheil, i was just trying to find out if the bird would lurch forward

#### Alexander

Of course, bird will slam into windshield. Braking is equivalent to increase in g (and tilting it forward).

#### Thomas

Re: Re: inertia

Originally posted by LURCH
I think not. Like the hellium balloon, the humming bird rides the air within the vehicle. Admittedly, the humming bird is less bouyant than the balloon, but it is also far less massive than a person
Buoyancy depends on the density of an object, not its mass. As the humming bird has a higher density than air but the helium balloon a lower density, they will not behave identically, i.e. the humming bird will fly against the windshield if you brake the car (unless it can react very quickly and brake as well).

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