Bird inside a box conundrum
- Thread starter Yoga Face
- Start date
If you were hovering 2 feet above your scale your weight wouldn't show up.[/QUOTE]
Indeed if the box had no top and a bird flew into the box the bird's weight would not be registered unless the bird landed
But the bird is inside closed box and his wings are moving and disturbing the air creating pressurized air currents pressing on the boxes bottom so does this change things
That would be my belief as well except I do not think the box would ever weigh less than 5 kg
I love these questions if only I were smart enough to know the definitive answer
I suspect the answer is yes as when the wings are moving downward they are creating air pressure downward but leaving a vacuum above the wings same thing the other way when wings are moving upwards
So the box may weigh less than 5 kg at some point and more than 5 kg at some point but I suspect this effect is canceled out somehow as the box is self contained but i am guessing
Never thought of that
but the bird would hit the top of the box first But lets say it is a mechanical bird on a pedestal inside the box
On its own the pedestal would fly away but what happens when it is attached to the bottom of the box would the box fly away
If the box top was removed I would say the answer is yes but with the box enclosed
I would guess no as all the forces are contained within the box but WTF do I know
Weight of the trailer was unchanged regardless of whether the birds were landed or flying.
Also confirmed it with an RC helicopter.
So the answer to the OP's question is 6kg.
Newton's 3rd law: For every action there is an equal and opposite reaction.
As the bird uses it's wings to lift it's 1kg body up, the air pushes down with 1kg force so the weight on the scale stays the same.
If the box is closed- everything inside the box is also included in the weight. Including the air. (Which won't register unless you have a REALLY GOOD scale which measures even the smallest amount. It the bird is also contained inside the box, then it doesn't matter if its flying around inside or landed.
So what if the box had a hole in the top
Would the total weight decrease by the size of the hole until the weight of the bird vanished
I mean if the box had no top, which is the biggest possible hole, and a bird flew into the box surely the birds weight would not register until it landed on the bottom of the box
Exactly.
The bird must exert a vertical force of 1 kg or 9.81 Newtons downward on the air in order to maintain lift. Since air is a fluid it (the fluid) then pushes down on the bottom of the box by a force of 9.81 Newtons as well.
The bird pushes down on the air, the scale pushes up on the box.
What if it is gliding is it the same thing. I suspect the 1 kg of weight is still imparted to the fluid air
Also what happens when the wings are moving upward is it still the same for now the force is against the roof. Would that lighten the box
What if there is a hole in the box
What if the birds legs were attached by a string to the bottom of the box could the flying bird lift the box off the scale
If a helicopter was attached to the bottom of a box would the box fly
How cool is that a flying box
I suspect that is how UFO's fly
I mean they can hover then take off vertically so maybe they got a helicopter inside
there is a difference between weight aqnd mass, the mass involved does not change the weight does
