I was reading this on reddit:
If you were in an elevator accelerating upwards which, you might experience a force of +2g. And if the elevator was accelerating downwards very quickly, you might actually feel an upwards force of -0.5g. That's what a negative g-force is, when it feels like you are falling up.
So I understand that the case scenario when an elevator is accelerating upwards, the net force on the person is in the up (positive) direction so the force applied by the person in reaction is in the down (negative) direction, which is positive g-force.
But I don't at all understand how you will feel an upwards force of -0.5g when an elevator is accelerating downwards. Because when in an elevator, accelerating downwards at theoretically $4.9m/s^2$, the force normal will still be upwards (as it's preventing free fall), but will be less than if there was no acceleration (less weight). But the reaction force therefore is downwards. So this is still just like the scenario when the elevator is accelerating upwards!
Or am I misreading this? Does this person actually mean if the elevator is somehow accelerating downwards at 1.5 times the acceleration of gravity? In that case, I don't see how this would make any sense.