[jonsen]

I don’t think it was an attack on your use of language. Even if most probably don’t agree that you are helping illiteracy by alternative use of well defined concepts.

It’s factually wrong to say that the net force is zero at the peak, when what is zero, is the vertical speed.

What was questioned was the feeling of weightlessness. You imply that weightlessness is only felt at the peak of the parabolic path. When the ball leaves the throwers hand, the only force, disregarding air resistance, acting on the ball is the force of gravity, until it hits the ground. Someone inside the ball will feel weightlessness all the way from leaving the throwers hand to hitting the ground. There is no special feeling at or around the peak.

[TangoTrotFox]

You're completely correct. I unintentionally implied weightlessness only at the parabolic peak. And I think what you've said is how you should correct things. Words convey ideas. What matters is not the words, but the ideas. Correct the idea and things are clear, focus on the words and things tend to muddle.