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Author Topic: Would a suspended object move as the Earth moves?  (Read 1636 times)

thedoc

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Would a suspended object move as the Earth moves?
« on: 12/04/2014 10:30:01 »
Cuthbert asked the Naked Scientists:

I would like to know is it possible that if we take something OFF the ground and suspend it on air, eg a helicopter which is able to be on 1 position on air, not moving!

Now, let's say it's 400 metres above the ground, visible to us, and for 4 hours.

Can it be still in the same position above us or at a marked point or it would have moved if so how many kilometres?

I listen to you every Friday

Cuthbert.

What do you think?
« Last Edit: 12/04/2014 10:30:01 by _system »

mybigfatcat

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Re: Would a suspended object move as the Earth moves?
« Reply #1 on: 11/04/2014 18:33:52 »
It stays at the same position relative to the person on earth . This is because when we initially moved the object to 400 meters above the earth it already had the same westerly movement (momentum) imparted to it by earth's rotation.  It continues to rotate with the earth at that position above it (as does the air (generally)).
BFC

CliffordK

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Re: Would a suspended object move as the Earth moves?
« Reply #2 on: 11/04/2014 20:03:11 »
Yes, if it is in a moving or rotating frame, then it will move or rotate with the frame.

However, you have to define what you mean by "suspended".  What about wind?

Orbital Dynamics are somewhat interesting.  On Earth it is hard to reach orbit until the atmosphere rarefies at about 100 miles or 160 km in altitude, at which point one can more or less stay above the planet.

As the orbital distance increases, both the velocity and angular velocities decrease until one hits the gesynchronous or geostatonary orbits when one seems to be "suspended" above the planet.

Ocean Balodiya

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Re: Would a suspended object move as the Earth moves?
« Reply #3 on: 16/04/2014 09:45:20 »
it will move... because... earth is a non inertial frame of reference...
but acceleration is very small ... so not noticeable... when we are viewing it...

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Re: Would a suspended object move as the Earth moves?
« Reply #3 on: 16/04/2014 09:45:20 »