From: Andria Erzberger (ALErzberger@lbl.gov)
Date: Mon Jan 14 2002 - 11:11:52 PST
Message-ID: <3C432D78.57D682FD@lbl.gov> Date: Mon, 14 Jan 2002 11:11:52 -0800 From: Andria Erzberger <ALErzberger@lbl.gov> Subject: Re: pinhole angular momentum
You definitely should do some on ang. mom. before the Olympics! It certainly
relates to spins in ice skating, the flips in ski jumping acrobatics (whatever
it is called) and gymnastics, and the spin on a football.
In astronomy a great example is the faster rotation of neutron stars, black
holes as massive stars collapse.
Look at Hewitt's Conceptual Physics for ideas.
The old spinning stool with weights in the hands, pulled in and out, must be
done by every student so that they can FEEL it.
There is a toy (sphere made of connectors) that collapses from a 3-4 ft sphere
to a diameter of a few inches. If you drop it while it is spinning, it will
collapse and thus spin faster.
And, of course there are gyroscopes and gyroscopic toys that illustrate that a
rotating object resists a change in its motion. Car and other objects use
flywheels for that reason.
If you have a demo bike wheel, show that a torque on it, causes a motion
perpendicular to the axes of the wheel and the torque. If you don't have one,
have the students lean to one side while riding a bike (don't use hands to
steer); the bike wheel will turn in that direction.
I could go on and on, but yes, angular momentum is very important in many
areas, and the conceptual ideas are easy to see/feel.
Andi
MC elover wrote:
> hey y'all
>
> i had an important revelation yesterday about angular
> momentum as i was wrapping up my yearly 10 minute
> super-lecture. most physics teachers end up in the
> same boat as me--angular motion is the last topic of
> the semester and it usually gets a quick and unworthy
> few days with angular momentum being something that
> gets barely mumbled as i try to explain why the spinny
> stool does its magic.
>
> it hit me, though: angular momentum is an incredibly
> important topic!!! from atoms to galaxies, angular
> momentum reaches far into many physical phenomena.
> conservation of angular momentum could be the most
> important law in all of physics for it governs the way
> matter itself is contructed.
>
> please tell me that some of you out there actually
> spend time discussing angular momentum. and let us
> all know how you go about it in a conceptual,
> non-mathematical way. this semester may be over, but
> we should all strive to give angular momentum its due
> next year.
>
> yours in spinnyness
> --eric
>
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