From drela at MIT.EDU  Sun Feb 12 14:42:37 2006
From: drela at MIT.EDU (Mark Drela)
Date: Sun, 12 Feb 2006 14:42:37 -0500
Subject: [Unified-mailman] Fluids question F1
In-Reply-To: Your message of "Sun, 12 Feb 2006 14:33:38 EST."
	<5.2.1.1.2.20060212142836.025771e0@po14.mit.edu> 
Message-ID: <200602121942.k1CJgbXo026008@orville.mit.edu>


>So do I have to calculate the acceleration of the plane 
>from t=0 to t=4. a=(v2-v1)/delta t or
>are you saying that the acceleration 
>is so small during the brief rotation period that I can say acceleration=0 
>and that v is just a constant=vtakeoff

The latter.

But the reason why you can assume v=constant over the rotation
is not because acceleration is small.  It's because the rotation
time interval  delta t = 4s  is short enough to produce only 
a neglible velocity change v2-v1 during the rotation.  So
v2 ~ v1 ~ vtakeoff