Physics Question!

90 Night Elf Druid
13100
So I've been thinking about this question on and off for awhile without giving much effort into figuring it out (since physics is not one of my friends), so here it is:

Let's say you have an RC helicopter and you're on an airplane. If you have the RC helicopter levitating perfectly still in the air (let's say.. in the aisle of the airplane), then will it stay still and move with the speed of the airplane? Or will it move backwards because the plane is moving forwards?
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90 Troll Shaman
13965
Is the plane already moving before the helicopter takes off or does the plane move once the helicopter is in the air?

If the plane is already moving the helicopter will hover in place relative to the plane. If the plane starts moving while the helicopter is in the air the helicopter will move backwards relative to the plane.

It has to do with one of Newtons Laws (I forget which number it is) which says "An object in motion will remain in motion, and an object at rest will remain at rest until an external force acts upon it".

If the plane is already moving when the helicopter takes off, the helicopter is at rest relative to the plane, meaning that they both have the same forward velocity. The position of the helicopter won't change relative to the plane until something acts on either the plane or the helicopter to change their trajectory.

If the airplane starts moving after the helicopter has taken off, then initially the airplane and helicopter are both at rest relative to the ground. Once the plane moves the helicopter is still at rest relative to the ground, but not relative to the plane, so the helicopter will appear to move backward to passengers on the plane.
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90 Goblin Warrior
16410
Here is should happen when you have the helecopter flying before takeoff.

You would see the helecopter shift some finite distance to the rear of the plane depending on how fast the airplane accelerates. The air behind the helecopter will act as a cushion for the helecopter and cause it to accelerate with the plane, but it won't accelerate exactly as fast as the plane.

If the plane goes fast enough in a short amount of time it will be able to overpower the wind resistance and make the helecopter hit the backwall.

If you sucked all the air out of the plane and the helecopter could magically hover you would see the helecopter crash into the rear wall everytime because there wouldn't be a cushion to push the helecopter to go with the airplane before hitting a wall.
Edited by Baddies on 6/26/2012 6:13 AM PDT
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90 Tauren Shaman
0
...and the helecopter could magically hover...

Okay, I missed this the first read through, lol.
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89 Night Elf Death Knight
3140
So I've been thinking about this question on and off for awhile without giving much effort into figuring it out (since physics is not one of my friends), so here it is:

Let's say you have an RC helicopter and you're on an airplane. If you have the RC helicopter levitating perfectly still in the air (let's say.. in the aisle of the airplane), then will it stay still and move with the speed of the airplane? Or will it move backwards because the plane is moving forwards?


Inside or outside of the aircraft, for the RC helicopter?

If the RC is inside, it should drop as the rotors must be moving to generate lift. If the RC is outside, it'll be shredded most likely due to the velocity of the aircraft; they tend to be above 200 mph in speed. At least, that's my impression.
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If we consider the following:

The aircraft is moving at a constant velocity (no acceleration and inertia)
The aircraft cabin is a completely closed space.

Then the RC helicopter would not jerk back and would levitate still in the cabin.

Because the aircraft is moving at a constant velocity so is everything else withing the enclosed space of the cabin including the air if we neglect other disturbances inside the cabin. The cabin acts as if it was a closed system at rest.

If however the aircraft was accelerating the air within the cabin would not provide sufficient friction(air resistance) to the helicopter. So once the helicopter leaves the floor of the aircraft it will accelerate much slower than the rest of the cabin and fly back till it hit a solid object like the wall that will provide it with enough friction to apply force and thus acceleration.
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85 Dwarf Hunter
8525
So I've been thinking about this question on and off for awhile without giving much effort into figuring it out (since physics is not one of my friends), so here it is:

Let's say you have an RC helicopter and you're on an airplane. If you have the RC helicopter levitating perfectly still in the air (let's say.. in the aisle of the airplane), then will it stay still and move with the speed of the airplane? Or will it move backwards because the plane is moving forwards?


it will move toward the tail of the aircraft but it will be hardly noticable. this is also obsevrable with craft relative to the earth and is why spacecraft tend to launch in a west to east direction
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I saw a video shot on the International Space Station.

There was a object hovering in the Destiny Module.

They ignited the service engines to boost the ISS to a slightly higher altitude.

The object stayed perfectly still while the ISS accelerated forward.

This gave the appearance that the object was moving backward inside the station.

The narrator explained why the object did that but I have forgotten most of his explination.

I do know that the air in the station had no effect on the object.
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90 Blood Elf Mage
9985
It's the same as tossing a ball up and down in the plane. It won't fly back at 600mi/h and kill everyone on board, it will simply go up and then gravity will bring it back down. You and the ball are already moving at 600mi/h relative to the ground.
Edited by Tabuu on 7/9/2012 9:40 PM PDT
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90 Draenei Paladin
11205
If the motion is constant, then the helicopter will share the plane's speed as the plane is serving as a microcosm for the helicopter. So far as the helicopter is concerned, there is nothing outside the plane.

If the plane's motion changes however, the helicopter will still have the inertia before the cange and will change accordingly due to the air inside being a fluid.. (ie the plane goes down and the helicopter will rise up) The more drastic the change on the plane, the more drastic the opposite change will be on the helicopter.
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85 Dwarf Hunter
8525
07/09/2012 09:40 PMPosted by Tabuu
It's the same as tossing a ball up and down in the plane. It won't fly back at 600mi/h and kill everyone on board, it will simply go up and then gravity will bring it back down. You and the ball are already moving at 600mi/h relative to the ground.


lol loss of coffee, yes
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