# Circular Motion and resultant force

1. Jan 29, 2016

1. The problem statement, all variables and given/known data

2. Relevant equations
F= mv^2/r
v = angular vel* r
3. The attempt at a solution
resultant force= ma-frictional force
= mv^2/r - mg*meu
= (angular vel)^2mx - mg*meu
But then how do I get the angular speed when I don;2 know the resultant force?

2. Jan 29, 2016

### Staff: Mentor

Only one (horizontal) force acts on the mass.

3. Jan 29, 2016

I don't understand.

4. Jan 29, 2016

### Staff: Mentor

Please identify the forces acting on the mass.

5. Jan 29, 2016

There is no centripetal force as the mass is not accelerating.
There is the friction force and centrifugal force

6. Jan 29, 2016

### Staff: Mentor

That would be true if viewed from the rotating frame, which requires the inertial centrifugal force. If so, what is the acceleration?

Or you can view it from the usual inertial frame, where the only force would be friction and there would be a centripetal acceleration.

7. Jan 29, 2016

so F=mv^2/r
mv^2/r=N*meu
v*angular vel* m = mg*meu
so angular vel = g*meu/v
as v= angular vel* x
angular vel^2=g*meu/x
so angular vel = (g*meu/x)^(1/2)
Which is the answer, thank you!