Physics question on Dennis

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wxcrazytwo

Physics question on Dennis

#1 Postby wxcrazytwo » Fri Jul 08, 2005 11:32 am

Okay physics question. What effect does inertia have on Dennis? I mean when it interacts with land to its right is the centripedal force going to keep it going towards its right, despite the high pushing it towards its left?


Example.

When you are driving a car and you hit a puddle with your right tire, the care will start to pull to its right because of the centripedal force pulling the object towards its right.

So, I am asking what effect does interaction of land have on Dennis or will it?
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#2 Postby PurdueWx80 » Fri Jul 08, 2005 11:37 am

It actually has more to do with the balance of forces - and the main factor here is friction. The car pulls right because suddenly there is no friction between the tire and the surface (becasue of the water). It's also sort of a different scenario, because the left tires will still have traction and will accelerate the left side of the car, which is what causes the rightward shift.

If you use the same general idea with Dennis - the storm shouldn't pull right, but will instead hug the coast (or "pull" left a bit) - trying to stay over the lowest-friction surface possible (the water). Steering flow can obviously alter this, but I think we'll see the storm huge the coast for a while before going inland.
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Re: Physics question on Dennis

#3 Postby jasons2k » Fri Jul 08, 2005 11:47 am

wxcrazytwo wrote:Okay physics question. What effect does inertia have on Dennis? I mean when it interacts with land to its right is the centripedal force going to keep it going towards its right, despite the high pushing it towards its left?


Example.

When you are driving a car and you hit a puddle with your right tire, the care will start to pull to its right because of the centripedal force pulling the object towards its right.

So, I am asking what effect does interaction of land have on Dennis or will it?


See thread on Joe B. @ 10AM - there is an explanation of this.
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#4 Postby dolphinslady » Fri Jul 08, 2005 11:51 am

PurdueWx80 wrote:but I think we'll see the storm huge the coast for a while before going inland.


Freudian slip? I laughed! LOL
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#5 Postby PurdueWx80 » Fri Jul 08, 2005 11:53 am

LOL hahaha - sorry about that.
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Re: Physics question on Dennis

#6 Postby Windy » Fri Jul 08, 2005 12:02 pm

wxcrazytwo wrote:Okay physics question. What effect does inertia have on Dennis? I mean when it interacts with land to its right is the centripedal force going to keep it going towards its right, despite the high pushing it towards its left?


Example.

When you are driving a car and you hit a puddle with your right tire, the care will start to pull to its right because of the centripedal force pulling the object towards its right.

So, I am asking what effect does interaction of land have on Dennis or will it?


I think you are misunderstanding what centripetal force is. The car example you cite has nothing to do with centripetal force -- I think you're thinking of force vectors there.

Someone will correct me if I'm wrong, but I'm guessing that hurricanes are probably mainly steered by 700 to 500 mb features and probably aren't terribly affected (in track, anyway) by land features.

The main drive of the centripetal force in a hurricane is the central low pressure; the coriolis effect gives the winds a slight counter-clockwise bias, which sets the whole system a 'spinnin.
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#7 Postby tw861 » Fri Jul 08, 2005 12:06 pm

Key west radar seems to show Purdues theory playing out.

http://www.srh.noaa.gov/radar/loop/DS.p ... kbyx.shtml
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#8 Postby coriolis » Fri Jul 08, 2005 12:23 pm

As someone who's been schooled in physics, but not met, I'll throw in my 2 cents. The #1 rule in physics is to get the definitions straight.

Centrifugal force acts outward from the center of the rotation. It's what makes things fly outward from the center of rotation. Centripetal force is the force that acts inward towards the center of rotation, such as gravity in an orbital situation. In the case of a hurricane, the central low pressure provides the centripetal force which holds the thing together. The coriolis effect causes the movement to occur perpendicular to the force vector towards the center, hence the rotation.

One other effect that no one has mentioned is that the friction of the mountains would slow the rotation on that side, causing the air to pile up somewhat. This would cause an increase in pressure on the landward side giving a gentle push back towards the ocean. If the steering currents are pushing inland, there could be some degree of shear exerted on the whole system. Add to that, the loss of energy from warm water over land, and yadda yadda yadda.....
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#9 Postby wxcrazytwo » Fri Jul 08, 2005 12:49 pm

great freaking post coriolis.
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