Answer:
a) 
b) 
c) Towards the center of the centrifuge
Explanation:
a)
Becuse the centrifuge rotates in circular motion, there's an angular acceleration tha simulates high gravity accelerations

with r the radius and ω the amgular velocity, in or case
so:
and g=9.8
solving for ω:


b) Linear speed (v) and angular speed are related by:


c) The apparent weigth is pointing towards the center of the circle, becuse angular acceleration is pointing in that direction.
Yes i does. they cause more friction <span />
IMA = Ideal Mechanical Advantage
First class lever = > F1 * x2 = F2 * x1
Where F1 is the force applied to beat F2. The distance from F1 and the pivot is x1 and the distance from F2 and the pivot is x2
=> F1/F2 = x1 /x2
IMA = F1/F2 = x1/x2
Now you can see the effects of changing F1, F2, x1 and x2.
If you decrease the lengt X1 between the applied effort (F1) and the pivot, IMA decreases.
If you increase the length X1 between the applied effort (F1) and the pivot, IMA increases.
If you decrease the applied effort (F1) and increase the distance between it and the pivot (X1) the new IMA may incrase or decrase depending on the ratio of the changes.
If you decrease the applied effort (F1) and decrease the distance between it and the pivot (X1) IMA will decrease.
Answer: Increase the length between the applied effort and the pivot.