# Resonance Vibrations

1. Mar 5, 2009

### kdr

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

A front-loading washing machine is mounted on a thick rubber pad that acts like a spring; the weight W = mg (with g = 9.8 m/s^2) of the machine depresses the pad exactly 0.19 cm. When its rotor spins at ω radians per second, the rotor exerts a vertical force
F0=cos(ω*theta)
Newtons on the machine. Neglecting friction, determine at what speed (in revolutions per minute) resonance vibrations will occur?

2. Relevant equations
ω0=sqrt(k/m)

3. The attempt at a solution
I have F=kx with the weight as F, so kx=mg. So k/m=g/x. So ω$$_{0}$$=$$\sqrt{g/x}$$ With g=9.8 m/s^2 and x=.0019 m. Then I multiply by 60 to go from seconds to minutes and divide by 2*pi. So I get ω0=686, but this isn't right.