# How does the force change with distance in a centrifuge?

If there are two centrifuges spinning at the same speed but one has twice the radius of the other, the contents of which centrifuge will be forced against the outside wall the most? Or to paraphrase, does the centrifugal force get stronger or weaker the further the contents get from the axis, or does the outward force stay the same, given the speed of rotation remains constant?

$$a = \omega^2 r \tag{1}$$
where $r$ is the distance to the centre and $\omega$ is the rotation speed, or more precisely the angular velocity of the rotation.
In your question you specify that the rotation speed is constant, i.e. $\omega$ is constant. In that case equation (1) tells you how the centripetal acceleration $a$ changes with the radial distance from the centre $r$. The force on an object of mass $m$ is then simply $F=ma$.