Re: Newton e Hooke

Jonathan Thornburg [remove -color to reply] il 16/02/2025 09:55:36 ha
scritto:

In article <vnttl2$20mb1$1@dont-email.me>, Luigi Fortunati wrote

If I push the end A of a spring, do I compress it or accelerate it?
 
Obviously I compress it and accelerate it at the same time, because I
am not pushing the elastic body of the spring but only its point A.
 
I ask myself: how much of my force is dedicated to compression and how
much to acceleration?

>
In general the spring's center of mass accelerates AND the spring is
compressed.
>
But, it's not correct to say that only part of the applied force is
dedicated to acceleration -- actually, the spring's center-of-mass
acceleration is determined by *all* of the applied force, while at the
same time the spring compresses.

The acceleration of the center of mass cannot be determined by *all*
the applied force because that force does NOT act on the center of
mass!

If you refuse to watch my animation https://www.geogebra.org/m/mrjtyuwk
you cannot notice that the applied force Fa (black) acts on point A"
and, before it can reach C, it must confront the opposing blue force.

The question is simple: does the opposing blue force in my animation
exist or not?

Luigi Fortunati