Find the critical rotation rate

[Milotoadfoot]

Homework Statement

The tumbler in an upright clothes dryer rotates at a critical angular
velocity so that clothes passing over the top briefly experience weightlessness.
If the radius of the drum is 0.30 m, what is this critical rotation rate? (Express
your answer in both radians per second and revolutions per min (RPM).) At
this rate, what is the apparent gravity felt by the clothes when they pass over
the bottom? (Express your answer in multiples of g.)

Homework Equations

a_rad=v²/R

The Attempt at a Solution

I don't see how we can extrapolate a critical rotation rate from the given equation. Maybe I am just missing something or are we looking for V_f?

 

[gneill]

Consider what the term "weightlessness" means and implies with regards to net acceleration.

 

[mfb]

You'll need the angular velocity for the answer, but you can start with the velocity if you like.
There is no need to extrapolate anything. When do you get weightlessness?

 

[Milotoadfoot]

You get weightlessness when g=0

 

[gneill]

You get weightlessness when g=0

But g is not zero. It's a constant 9.8 m/s². What other acceleration is in play? What's the net acceleration?

 

[Milotoadfoot]

Well we care about the acceleration of ω right?

 

[mfb]

ω is constant, there is no "acceleration of ω". There is an acceleration that has a relation to ω, yes.

 

[blintaro]

Perhaps "weight" can be thought of as normal force exerted on the body.