Why does a heavier sphere fall faster in a liquid ?

[KingCrimson]

why do heavier balls fall faster in liquids ?, if F=mg-drag, a heavier ball would have greater mg, but the acceleration is given by F=ma, therefore mg-drag = ma, a = (mg-drag)/m.
I can't see how a heavier ball would fall faster.

 

[Bandersnatch]

You've got $a=g-F_D/m$. (minus is up here) If you increase mass, g is reduced more or less?

 

[TESL@]

$F=ma=mg-F_b-F_d$ where $F_b$ is buoyant force and $F_d$ is drag.

Then; $a=g-F_b/m+F_d/m$, so if you have two balls of same volume but different mass, the larger mass will have a higher acceleration.

 

[KingCrimson]

You've got $a=g-F_D/m$. (minus is up here) If you increase mass, g is reduced more or less?

g is constant, but Fd/m is reduced, I see it now :D thanks.