The Physics of Force

[Frank_B]

You're getting hung up on the definition of acceleration. Even if an object is sitting on the ground with 0 velocity, we still describe the force in terms in terms of acceleration (32.2 feet/sec2) because that is what would happen if the object was in free fall. To show this in your scenario, let's imagine that you have gotten the bar off the ground and it is now moving up at some constant velocity. Let's then imagine that the force of gravity suddenly disappeared while you were moving the bar up at a constant velocity. Your bar would in fact then start accelerating upward at a rate of something slightly above 32.2 feet/sec2.

Yes. I understand that. My dilemma was with the equation relative to my experience. Usually math does an excellent job at describing reality, and in this case it does as well, but it’s misleading. The sum force of gravity (-500) and the lifter’s pull (+500) means the net force on the bar is 0 when the bar is moving at a constant rate.

I was under the flawed initial assumption that the equation described the force I was putting into the bar ONLY and not the sum total of all the forces in different vectors acting on the bar.

I'm not sure I'm understanding the problem, but if you apply 0 force to the bar, then it will fall at the rate gravity wants it to fall at, slowed only momentarily by the bar accelerating your face towards the floor. (assuming you're still holding the bar)

If F = M*A, and acceleration is 0, and anything multiplied by 0 is 0, then F = 0. This is true in this scenario, but F is equal to TOTAL FORCE from all directions, including the force gravity is applying down, as well as the force I am applying up.

[Marc Brainich]

This thread is a total psyop. Zeno proved 2500 years ago that movement is philosophically impossible. I am therefore sticking to the couch.

[VNV]

This thread is a total psyop. Zeno proved 2500 years ago that movement is philosophically impossible. I am therefore sticking to the couch.

Zeno didn’t appreciate infinite sums, but neither do modern economies. So I sympathize.