Re: [Phys-L] Dirigible Flight Question

["John Clement" <clement@hal-pc.org>]

I am always looking at what might help students and not in fancy
engineering.  But the idea of drag along air is intesting.  Sure it is a
very difficult problem, but students come into physics with zero
understanding of buoyancy, so some slightly challenging problems involving
it could be good on top of a good tutorial.

Students need to be able to visualize limiting cases such as acceleration at
zero velocity and then at terminal velocity, without the necessity of
calculating things.  So a lot of details can be swept under the qualitative
graph line.  When one has students just draw qualitative graphs it is quite
revealing what they think is happening, even when they observe the situation
in a simulation or video.

John M. Clement
Houston, TX 

> -----Original Message-----
> From: Phys-l [mailto:phys-l-bounces@phys-l.org] On Behalf Of 
> Bernard Cleyet
> Sent: Monday, November 05, 2012 5:08 PM
> To: Phys-L@Phys-L.org
> Subject: Re: [Phys-L] Dirigible Flight Question
>
>
> On 2012, Nov 05, , at 11:44, John Clement wrote:
>
> > The NTN2 analysis is really a good way of brining home the 
> idea that 
> > the total mass is the mass of the balloon, helium, and the 
> hanging mass.
>
>
> There's also added mass from the air that "sticks" to a moving object.
>
> This is an important air correction*** when using a simple 
> pendulum to find g  -- 
>
>
>
> ***Along with buoyancy and damping.  It's the third in 
> magnitude of 16 corrections.
>
>
> Check out:    The pendulum--Rich physics from a simple system
>
> Am. J. Phys.  54 112 ff.
>
>
> bc v. often uses "scare" quotes.
>
>
>
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