Plane on conveyer: Will it ever take off?
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From: High Point
Wouldnt the belt be just the same as an airplane taking off from an aircraft carrier essentially. Both the boat and belt are moving... even if not quite the same I say the aircraft definitely takes off.
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From: Yorba Linda, CA
Originally Posted by r_duff,Dec 2 2005, 03:24 PM
i dunno if this is a good example or not, but:
If you have a helicopter whos blades spin at 2000 rpm clockwise, and it flies into the center of a tornado also spinning at 2000 rpm clockwise, wouldnt the helicopter fall because the blades are not moving relative to the air its supposed to be pushing against??
Same thing with the plane. its wings are not pushing against the air.
If you have a helicopter whos blades spin at 2000 rpm clockwise, and it flies into the center of a tornado also spinning at 2000 rpm clockwise, wouldnt the helicopter fall because the blades are not moving relative to the air its supposed to be pushing against??
Same thing with the plane. its wings are not pushing against the air.
Second, what idiot would try to fly a helicopter into a tornado?
Third, if the plane moves relative to the air - and the engines of the plane work to ensure that exactly this happens - the wings will generate lift; what's happening on the ground is irrelevant.
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From: City
Originally Posted by magician,Dec 6 2005, 03:23 PM
First, a helicopter of any reasonable size cannot have a rotor spinning at 2,000 rpm. If the blades were, say, 10 feet long, the tip of the blade would be traveling at 1,428 mph - well over Mach 2 - and the blades would shatter; a helicopter cannot have the tips of its blades exceed Mach 1 without being destroyed.
Second, what idiot would try to fly a helicopter into a tornado?
Third, if the plane moves relative to the air - and the engines of the plane work to ensure that exactly this happens - the wings will generate lift; what's happening on the ground is irrelevant.
Second, what idiot would try to fly a helicopter into a tornado?
Third, if the plane moves relative to the air - and the engines of the plane work to ensure that exactly this happens - the wings will generate lift; what's happening on the ground is irrelevant.
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From: Pembroke
I'm a business major who failed 1st year engineering...so I'll leave the free body diagrams to the real engineers.
VCR vs Balloon. First, forget about the car. Say you have a VCR and a balloon and you're standing on the ground. You throw each one using the exact same force from your arm.
The VCR will go farther of course, because of two things - momentum and air resistance.
Again, not an engineer, so I'm not sure of the exact formula. But momentum is a combo of mass (weight) and velocity. Both the balloon and VCR will start out at the same speed at the point of release of the throw, but the heavy VCR (momentum) along with its shape, will overcome the air resistance and decelerate slower, and travel farther. The balloon is light (less momentum) and less aerodynamic, therefore it will decelerate at a greater rate and travel less distance.
in the car, all the objects are going 45mph. When the car stops, unrestrained objects will continue to travel unless acted upon by another force. Yes, the VCR will shoot forward.
Here's my shot in the dark, but I think the balloon will too, because in a moving car, the air inside the car is also moving at 45mph - assuming the car is sealed. So the air resistance doesn't exist as the air is moving along with the balloon. Its like going back to your front lawn, and you have a 45mph tailwind, then you throw the balloon. THe balloon will travel much farther.
VCR vs Balloon. First, forget about the car. Say you have a VCR and a balloon and you're standing on the ground. You throw each one using the exact same force from your arm.
The VCR will go farther of course, because of two things - momentum and air resistance.
Again, not an engineer, so I'm not sure of the exact formula. But momentum is a combo of mass (weight) and velocity. Both the balloon and VCR will start out at the same speed at the point of release of the throw, but the heavy VCR (momentum) along with its shape, will overcome the air resistance and decelerate slower, and travel farther. The balloon is light (less momentum) and less aerodynamic, therefore it will decelerate at a greater rate and travel less distance.
in the car, all the objects are going 45mph. When the car stops, unrestrained objects will continue to travel unless acted upon by another force. Yes, the VCR will shoot forward.
Here's my shot in the dark, but I think the balloon will too, because in a moving car, the air inside the car is also moving at 45mph - assuming the car is sealed. So the air resistance doesn't exist as the air is moving along with the balloon. Its like going back to your front lawn, and you have a 45mph tailwind, then you throw the balloon. THe balloon will travel much farther.
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From: Yorba Linda, CA
Originally Posted by r_duff,Dec 6 2005, 06:27 PM
. . . i just threw out 2000 RPM arbitrarily.
The estimates ranged from a low of fifty feet (!) to a high of one mile (!!): one student thought that the entire building was as tall as another student thought one floor was!
A reasonable approach would be to estimate that each story is about ten feet high, and there are about 100 stories, so the building is about 1,000 feet tall.
The ability to estimate relatively accurately is not a bad skill to possess.