A 60-lb disk is attacked with an eccentricity e = 0.006 in. to the midpoint of a vertical...

A 60-lb disk is attacked with an eccentricity e = 0.006 in. to the midpoint of a vertical shaft ABwhich revokes at a constant angular velocity ωf. Knowing that the spring constant kfor horizontal movement of the disk is 40,000 lb/ft. determine (a) the angular velocitv ωfat which resonance will occur, (b) the deflection r of the shaft when ωf= 1200 rpm.