"The Third Law, as you may recall, is “for every action, there is an equal and opposite reaction.” When I sit on a chair, I exert downward force on the chair. That is an action. The chain exerts an equal and opposite upward force. And I am suspended in air. Physics."
Actually not true. The Earth exerts a gravitational force on you, and you exert an equal gravitational force on the Earth. Those are the paired forces that make up the Third Law in this case. The forces between you and the chair are reaction forces that arise because of the mutual attraction between you and the Earth. Sorry to be a pedantic physics nerd!
Thank you for the correction. I would never suggest anyone follow my instruction in regard to fixing a car, treating a disease, or understanding the fundamentals of existence.
Aren’t you confusing the third law which does say what Dan described with newton’s law of universal gravitation?
The gravitation law describes why you and the earth are pulled toward each other with equal forces.
It doesn’t describe why you stop moving toward the centre of the earth when you bum comes to rest on a chair of sufficient construction.
That is the third law which says you will stop moving if the chair can exert a force equal to the gravitational force stopping you. This force is generated by the work of all theses atomic and molecular forces holding the chair together, this is best illustrated by trying to sit on weaker and weaker chairs.
Yes, now that I reread Dan’s comment I see he did not mention gravity as one of the forces, so his comment is correct. Often people will say “gravity pulls me down and the chair pushes me up because of the Third Law”. That statement is not correct.
In my haste to be a know-it-all, I misread the original comment.
I guess the moral here is there can be no learning without humility. And maybe that’s what was wrong with Roger Babson—the unwillingness to believe he could be wrong.
"The Third Law, as you may recall, is “for every action, there is an equal and opposite reaction.” When I sit on a chair, I exert downward force on the chair. That is an action. The chain exerts an equal and opposite upward force. And I am suspended in air. Physics."
Actually not true. The Earth exerts a gravitational force on you, and you exert an equal gravitational force on the Earth. Those are the paired forces that make up the Third Law in this case. The forces between you and the chair are reaction forces that arise because of the mutual attraction between you and the Earth. Sorry to be a pedantic physics nerd!
Thank you for the correction. I would never suggest anyone follow my instruction in regard to fixing a car, treating a disease, or understanding the fundamentals of existence.
The good thing is you can annoy and correct others in the future. You're welcome ;)
Aren’t you confusing the third law which does say what Dan described with newton’s law of universal gravitation?
The gravitation law describes why you and the earth are pulled toward each other with equal forces.
It doesn’t describe why you stop moving toward the centre of the earth when you bum comes to rest on a chair of sufficient construction.
That is the third law which says you will stop moving if the chair can exert a force equal to the gravitational force stopping you. This force is generated by the work of all theses atomic and molecular forces holding the chair together, this is best illustrated by trying to sit on weaker and weaker chairs.
Yes, now that I reread Dan’s comment I see he did not mention gravity as one of the forces, so his comment is correct. Often people will say “gravity pulls me down and the chair pushes me up because of the Third Law”. That statement is not correct.
In my haste to be a know-it-all, I misread the original comment.
And here I was all prepared to be wrong.
I guess the moral here is there can be no learning without humility. And maybe that’s what was wrong with Roger Babson—the unwillingness to believe he could be wrong.
Dang I can’t fix my typos.