Re: Newton's 3rd law is wrong

Arm wrestling: initially, hand A pushing to the right and hand B pushing to the left are still because the action and reaction are equal and opposite.

If the two opposing forces remained *always* equal (as Newton's third law states), they would never start moving to the right or even to the left: they would remain eternally still.

Ibex A and B fight horns against horns and are still because the action of ibex A to the right is perfectly equal and opposite to the reaction of ibex B to the left: how could they both start moving (accelerate) to the right or to the left if neither of the two forces prevailed over the other? They couldn't and they would remain eternally still!

Team A pulls the rope to the right with the same force with which team B pulls it to the left and they remain still until when? Until the balance of the two opposing forces is broken and one of the two forces prevails.

The rope between the horse and the stone moves with uniform speed until the force of the horse pulling to the right is equal and opposite to the friction of the stone on the ground pulling to the left but when its speed increases (acceleration) the force of the horse cannot be equal to the resistance of friction!

In short, the perfect balance between action and reaction exists only when the two bodies (together) are still or move with uniform and rectilinear speed but not when they accelerate!

The young student who comes across this discussion will ask himself: are these simple considerations right or wrong?

Since they are contrary to the teachings he receives, he should immediately think that Newton is right and, therefore, that these considerations must be easily contestable by those who know more.

But then he would also ask himself: how come the discussion ran aground without anyone being able to refute it?

And the doubt would remain.

Luigi Fortunati