Richard Livingston il 20/11/2023 17:10:20 ha scritto:
>> In my animation https://www.geogebra.org/m/abg3ewgy if we click on the "Start" button, we see the "net" force 10 which accelerates the mass of the elementary particle A towards the right (according to the second law F=ma) and no force directed towards the left.
>> So far I have nothing to ask because everything is clear.
>> Then we select the checkbox to add particle B.
>> In this case, there is no longer the single particle (A) but there is the body AB formed by the set of the two particles A and B, so that the mass doubles and the acceleration is halved.
>> The force F=10 acts only on particle A which transmits the push to particle B.
>> In this way, an action and reaction relationship is established between A and B: particle A exerts a blue force towards the right on particle B and particle B reacts with a red force towards the left on particle A.
>> Question 1: Is it correct to say that these two blue and red forces are worth 5 and –5 respectively?
>> Question 2: Is it correct to say that a "net" force (5) to the right acts on particle A (blue force 10 minus red force 5) and a net blue force (5) acts to the right on particle B?
>
> Answer is yes to both questions, assuming both particles have the same mass.

Thank you.

Therefore, this red force –5 exists and is the inertial reaction of particle B against anyone who tries to change its condition of rest.

I ask you: what difference is there between this red force –5 of my animation and the one that Newton (talking about inertia) describes like this: "a body exerts this force (inertia) only when another force, impressed upon it, endeavors to change its condition"?

Luigi Fortunati

In my animation
https://www.geogebra.org/m/abg3ewgy
there is a blue force 10 directed to the right which generates an acceleration 10.

If I want to reduce the acceleration from 10 to 5, I need to apply a red
force –5 (directed to the left) on mass A, so that the net force on mass
A becomes equal to 5 and the acceleration also drops from 10 to 5 .

However, there is also another way to obtain the same result (reduce the
acceleration of A) without applying any force, just add the mass B (with
the appropriate box).

In this way, mass B generates a red force –5 on mass A, halving its
acceleration.

How is it possible that adding mass B (which is a scalar) acts *exactly*
like the force F=-5 (which is a scalar)?

Luigi Fortunati