What Frequency Causes the Box to Slide on a Rotating Platform?

[pooface]

Homework Statement

A box rests at a point 2.0m from the axis of a horizontal circular platform. The coefficient of static friction between box and platform is 0.25. As the rate of rotation of the platform is slowly increased from zero, at what frequency will the box first slide?

Homework Equations

The Attempt at a Solution

a.centripetal = mu(g)

=0.25(g) = 2.45m/s^2

a.centripetal=v^2/r

frequency=sqrt(a.centripetal*r)/2*pi*r = 0.176 rev/s

Have i done this correctly?

 

[hotcommodity]

I arrived at the same answer, but you'll probably want to use two sig figs because the coefficient of static friction and radius have two sig figs.