# the magnitude of gravity in real units

Hi, everyone, I have a question about the magnitude of gravity in real units. In si units, the magnitude of gravity is 9.8 m/s^2. So in real units, the magnitude of gravity is 9.8e-20 Angstroms/femtosecond^2. The value looks weird. Can you give me some suggestions? Best wishes!

Yours,

Jing

What do you mean by “looks weird”?

Oleg

lujing8556 <lujing8556@…127…> 7 ноября 2014 г. 15:25:01 написал:

What do you mean by "looks weird"?

or more importantly, what is it needed for? on the atomic scale, the
impact of gravity is negligible.

axel.

Dear Axel,

Thanks very much for your help. I need to consider the gravity of agregates in brownian dynamics simulation. The average size of these aggregates in my simulation is about 2 micrometer. But in my simulations, I cannot observe the obvious gravity sedimentation. So i doubt whether the magnitude of gravity in real units is right. Thanks very much. Best wishes!

Yours,

Jing

``````

Dear Axel,

Thanks very much for your help. I need to consider the
gravity of agregates in brownian dynamics simulation. The average size of
these aggregates in my simulation is about 2 micrometer. But in my
simulations, I cannot observe the obvious gravity sedimentation. So i doubt
whether the magnitude of gravity in real units is right. Thanks very much.

it is embarrassingly trivial math to prove whether it is correct or
not (it is: 10^-10/(10^-15)^2 = 10^-20).

thus something else is messed up: either your expectations of the time
scale of the sedimentation that you mention or your input parameters
or both.

If you are using fix gravity you should note that magnitude is in (force/mass units) which in real would be kcal/angstrom/gram. The conversion factor from m/s^2 to this unit is 2.388e-17

salam shoma?

If you are using fix gravity you should note that magnitude is in (force/mass units) which in real would be kcal/angstrom/gram. The conversion factor from m/s^2 to this unit is 2.388e-17