Constant Acceleration Downwards

1. Aug 25, 2013

nate99

I remember being taught that, due to gravity, we are always accelerating downwards. But how do you explain it?

Gravity is constant, and even if we are at rest, if I step on a scale I still get a weight of my mass X acceleration due to gravity. My forces vertically are balanced (me on the ground and the ground on me), therefore I have a constant velocity of no motion in the vertical direction.

But if I have no motion in the vertical direction then there is no change in velocity. I just stay at zero for velocity. So then how is my body ACCELERATING downwards? I completely understand that as soon as I jump or step off of a ledge and there is nothing to push up on me, my velocity will accelerate at 9.8 m/s2 in the down direction. But it's hard to understand how an object at rest is actually accelerating in the downward direction, unless I got my concepts mixed up, which often happens.

Thanks for the help!

2. Aug 25, 2013

Staff: Mentor

You aren't accelerating downwards while standing on the ground.
Gravity applies a force to your body, which would accelerate you at approximately 9.8 m/s2 if it could.

3. Aug 26, 2013

nate99

I see, I guess I just learned it wrong in the past. Thanks for correcting me