how come a helicopter hovers in the same spot when the earth rotates.?

Answer 1

Hey!,, Good question. This could sure disprove the scientific theory of that the Earth rotates.

I actually have know this helicopter pilot who told me that while hovering for 1 hour, his compass and GPS never moved for the entire hour showing the helicopter was in the same place for the past hour, despite or Earth rotating. Why didn't the compass at least change directions?

Answer 2

The Earth is rotating slowly. Every minute, the direction of travel of a point on the ground only bends through 0.25 degrees.

This slow rotation doesn't affect the helicopter very much. A touch on the controls will be enough to counter any slight effect due to the rotation of the Earth.

A rocket hovering, say, 300 miles above London would need to direct its thrust along a line that was almost directly down, but not quite. This is because the thrust would need to (a) counteract gravity, and (b) provide a constant small force towards the axis of rotation of the Earth and at 90 degrees to this axis. Imagine a plane containing the Earth's axis of rotation and the line between the rocket and the centre of the Earth. The rocket's line of thrust would be in this plane, and almost exactly downwards, but rotated slightly so that it pointed at a point on the Earth's surface somewhat south of the point directly beneath the rocket. The rocket's line of thrust would remain pointing at the same point on the Earth's surface all the time. This would ensure that the rocket would move in a circle centred on the Earth's axis of rotation. The rocket would be hovering above London, which also moves in a circle centred on the Earth's axis of rotation.

A rocket hovering 300 miles over the Equator would need to direct its thrust directly downwards, but the thrust would be slightly less than the weight of the rocket. There would thus be a small net downward force on the rocket, which would keep the rocket moving in a circle centred on the Earth's axis of rotation. The centre of the rocket's circular path would also be the centre of the Earth.

Any body which moves in a circle at constant speed must have a constant net force acting on it, and this net force must always point towards the centre of the circle. The magnitude of the net force must be ((mass of body) x ((speed of body) squared)) / (radius of circle)

I hope the information on the rocket is interesting to you. The helicopter situation is more complicated, because the motion of the helicopter is obviously affected by the motion of the atmosphere. The movement of the atmosphere relative to the Earth's surface, and the pressure variations within the atmosphere caused by the rotation of the Earth, are a complicated subject which I'm not an expert in! I'll just say that the reason that the atmosphere rotates at the same speed as Earth is the friction between the Earth's surface and the bottom of the atmosphere. The atmosphere is more-or-less hovering above the Earth (give or take some wind!), so it's pretty easy to hover a helicopter within the atmosphere.

Answer 3

Not sure this is gospel, but it's how i think of it... gravity is an equal constant downward force on all surface areas at all times which fixes objects in relation to the earth's surface, meaning to move up or down or left or right etc you need to physically move (i.e. use more energy than is being applied to that object by the gravitational field) so whoever said the earth pulls it along with it is kind of right.

It's the same reason that absolutley everything in the world isn't being hurled around like we're on a giant treadmill, or that a plane traveling against the rotation of the earth wont take longer to fly the same distance as a plane flying in the opposite direction.

Answer 4

The same reason as why a ball lands on the same spot when thrown vertically. The helicopter is rotating with the same angular speed as the Earth and, like everything else, it will continue to do so unless acted upon by another force. It is obeying Newton's laws of motion.

Answer 5

the point is the heli is also rotating with the earth at the same angular velocity. So as far as we and the earth are concerned the heli hovers at the same spot. But for somebody in space say mars would see the heli also revolving just like a moon.

Answer 6

Because the air it hovers in rotates with the earth

Answer 7

Because every object along with the helicopter is rotating with the same speed as earth

Answer 8

Because the pilot hovers in relation to the earth.

Answer 9

Because it hovers in relation to the ground and not the space

Answer 10

omg i dont even know where to start with this one! go to your library and look up gravity, physics and in fact you'd probably best start with the hungry Caterpillar. Its a very informative book and i believe one of George bush's favourites. Forms the backbone of all his policies.

Please someone answer this question I'm far to annoyed now. lol

P.S. Its actually quite a good, if slightly annoying question. Just ignore me im tired