Figure this out.
Take big box truck and put a 1000 pounds of canaries in it. Weigh the truck. The weight will be the truck plus 1000 pounds. Bang on the side of the truck so all the canaries are flying inside the truck and not touching it. Does the weight on the scale change? If so, how much? Remember, the canaries are flying inside the closed truck.
Something to think about instead of working
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AZhitman
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Hmmmm.
It's important to know whether the truck is a SEALED container, which (if the birds are to live for any length of time) it is not.
The truck scale measures the force gravity exerts on the truck in a downward direction. On the scale, the "weight" of the (UNSEALED) truck would REGISTER as less with the birds in flight because the scale would not measure the true weight of the truck plus the birds now. But this is a false fluctuation - The weight has not changed. A good example of this: If you ride an elevator while standing on a scale, it will change its reading, but your weight hasn't changed - it remains constant.
However, in a SEALED container (dead birds), the improbable (and short-lived) flight of the birds would NOT cause fluctuations in the weight of the truck. The volume of air AND the doomed birds would all remain constant.
After an hour of figuring, I hope that's correct....
It's important to know whether the truck is a SEALED container, which (if the birds are to live for any length of time) it is not.
The truck scale measures the force gravity exerts on the truck in a downward direction. On the scale, the "weight" of the (UNSEALED) truck would REGISTER as less with the birds in flight because the scale would not measure the true weight of the truck plus the birds now. But this is a false fluctuation - The weight has not changed. A good example of this: If you ride an elevator while standing on a scale, it will change its reading, but your weight hasn't changed - it remains constant.
However, in a SEALED container (dead birds), the improbable (and short-lived) flight of the birds would NOT cause fluctuations in the weight of the truck. The volume of air AND the doomed birds would all remain constant.
After an hour of figuring, I hope that's correct....
Is this a fluid dynamics problem? If the box is sealed, and if you take the average weight over time, wouldn't the average be somewhere between the truck and the truck+canaries? When a bird flaps its wings, it pushes on the air which displaces in various directions. Some of the force is transmitted to the surface under the bird (the scale), and some of the energy heats the air.
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nlzmo400r
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well heres one for ya, if u have a remotely controlled helicopter and you're riding in a school bus (all widows down) and youre sitting in a seat, you're keeping the helicopter stable in a hoover wihle riding in teh school bus at 45mph, does teh helicopter float to the back of the bus, or stay stationary??!!
Floats to the back of the bus. It's riding on the air, not the momentum of the vehicle. The chopper is not being affected by the bus' forward motion(assuming it's already hovering).
If you toss a ball to your buddy, while the bus is moving, you can't notice, but it's trajectory IS affected, however slight. It's slight because of the 1: velocity of the ball over it's trajectory.2: low mass of the object.
Now, when your bus is accelerating, and you toss that ball, the damn thing is gonna fly off and hit some girl in the head. The reason are the shifting momentum of the bus, you, and the low mass of the ball, which is too light (as it leaves your hand) to maintain momentum. No mass. The chopper is different as it does not depend on the bus' mass and forward momentum to maintain velocity, height. Make sense?
If you toss a ball to your buddy, while the bus is moving, you can't notice, but it's trajectory IS affected, however slight. It's slight because of the 1: velocity of the ball over it's trajectory.2: low mass of the object.
Now, when your bus is accelerating, and you toss that ball, the damn thing is gonna fly off and hit some girl in the head. The reason are the shifting momentum of the bus, you, and the low mass of the ball, which is too light (as it leaves your hand) to maintain momentum. No mass. The chopper is different as it does not depend on the bus' mass and forward momentum to maintain velocity, height. Make sense?
Helicopter's relative motion depends on it's inertia when it took off. Did it take off when the bus was stopped, or while the bus was already at a set speed?
How about outdoors? A wind gauge reads zero and you pilot a helicopter straight up, along a vector passing through the center of the Earth. Considering the rotation of the Earth and the measured wind speed, will the chopper move laterally with respect to it's point of take-off?
How about outdoors? A wind gauge reads zero and you pilot a helicopter straight up, along a vector passing through the center of the Earth. Considering the rotation of the Earth and the measured wind speed, will the chopper move laterally with respect to it's point of take-off?
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AZhitman
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DAEDALUS wrote:Relative to a fixed point on the road, yes. Relative to the lucky basturd, no.
Well said. You can work on my car ANYDAY.
Was I right with my canary-truck answer? I think it hinges upon the definition of "weight", which I'm unclear on.
My physics class was held in an auditorium with 300 students, one of whom was a rather attractive female who liked me better than she liked the subject matter. We both sat in the back and both passed with a C.
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AZhitman
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SmithSR wrote:Just think, you could throw a baseball from the backseat to the front(but why would you?) and you could be throwing a roughly 200MPH fastball. You'd probably catch quite a beating from the car's owner for doing so.
OUTSIDE the car (like hanging out of the sunroof) however, drag takes over (beyond a certain speed). Don't ask me how I know...
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Get240DiZzY
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AZhitman
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This takes us back to my prior post. The jar was sealed. So it doesn't matter if the flies/birds/Tino's mom were flying or sitting. The container + contents (air, birds, etc) all register on the scale.
In an unsealed container, we have a different issue. Let's imagine the sides/top of the truck are made of chickenwire. Again, the WEIGHT of the truck as registered may change.... But the mass of the container and it's contents remains stable.
In an unsealed container, we have a different issue. Let's imagine the sides/top of the truck are made of chickenwire. Again, the WEIGHT of the truck as registered may change.... But the mass of the container and it's contents remains stable.
AZhitman gets a cookie.
If the truck is not sealed (air leaks like a normal trailer), when the birds fly they are supported by the differences in air pressure on the top and bottom of their wings. None of the lifting forces would tranfer to the truck as long as they are far enough away from the floor for no air turbulance to reach. In this case the mass (weight) of the birds is supported by air pressure, not the truck so the scale would see just the truck.
If the truck is sealed (like the jar in the fly example). The scale would see the mass of the entire system; truck, birds, and contained air less the mass of the air displaced by the truck.
If it didn't work this way, every time a 747 flew over your head, you would feel 800,000 pounds on your head. A bad thing.
If the truck is not sealed (air leaks like a normal trailer), when the birds fly they are supported by the differences in air pressure on the top and bottom of their wings. None of the lifting forces would tranfer to the truck as long as they are far enough away from the floor for no air turbulance to reach. In this case the mass (weight) of the birds is supported by air pressure, not the truck so the scale would see just the truck.
If the truck is sealed (like the jar in the fly example). The scale would see the mass of the entire system; truck, birds, and contained air less the mass of the air displaced by the truck.
If it didn't work this way, every time a 747 flew over your head, you would feel 800,000 pounds on your head. A bad thing.
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Get240DiZzY
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"Relative to a fixed point on the road, yes. Relative to the lucky basturd, no."
Yes, but if youre standing on the bus while its moving, and you jump in the air, you land in the exact spot from which you first jumped, BUT, If the busdriver sees an s15 on the side of the road, and slams on the brakes to look at it, while youre in the air, you will land farther toward the front of the bus, from where you first jumped. and probably fall down and get hurt very badly.
LOL "critical mass".....
Yes, but if youre standing on the bus while its moving, and you jump in the air, you land in the exact spot from which you first jumped, BUT, If the busdriver sees an s15 on the side of the road, and slams on the brakes to look at it, while youre in the air, you will land farther toward the front of the bus, from where you first jumped. and probably fall down and get hurt very badly.
LOL "critical mass".....
ok, this is one I never figured out. Say you are riding in a skyline at the exact same speed that a bullet would leave the barrel of a gun. Say you are facing opposite the direction you are going and you pass by your friend and shoot the gun at him. Since you are going the same speed in the opposite direction of the bullet, would the bullet appear to float in the air to your friend on the side of the road, or would it just drop to the ground where it was shot from?
Bullets do not "float". They drop as fast as anything else under the force of gravity, and taking into account the effects of air resistance (negligible). A bullet fired hits its target only because it is allowed to drop for only a VERY short of time (.042 seconds assuming 1800 fps at 25 yards, .667" drop).
So if you fire the gun backward horizontally as you pass your friend (at 1800 fps), it will look to him like the bullet was simply let go, and it will fall to the ground (in .56 seconds, from a height of 5 feet).
Someone's been watching The Matrix.
So if you fire the gun backward horizontally as you pass your friend (at 1800 fps), it will look to him like the bullet was simply let go, and it will fall to the ground (in .56 seconds, from a height of 5 feet).
Someone's been watching The Matrix.