Re: [Phys-L] Demonstrating energy and levers

[Bernard Cleyet <bernardcleyet@redshift.com>]

On 2013, Nov 19, , at 20:28, Bernard Cleyet <bernardcleyet@redshift.com> wrote:

> Do your students “understand” potential E, as in Mg•h and 0.5 kX^2 (Hookian spring)**.  If so, use each at the ends of a lever.  Move the fulcrum about and (still) get equality.  If the fulcrum is not centered first balance the lever (with masses).  Then add mass to stretch the spring.  Obviously, I pray, with a multiplier less mass required to stretch a given distance, and the mass moves further.

bc prays he’s not mixed up and doesn’t think it’s necessarily a good method.  

=======================


Yup, jumped to a false conclusion (my favo. occupation).   Not only will the added mass stretch the spring, but it also raises the mass used to initially balance the lever (with the spring not quite stretched).  A complication.  Also since linear and (a principle of which JD is fond) I can’t remember it.  The spring may begin stretched also.

bc  not late enuf for that to be an excuse.