The disk shown, weighing 3 lb, rotates about O by sliding without friction over the horizo...

The disk shown, weighing 3 lb, rotates about O by sliding without friction over the horizontal surface shown. The spring is linear with constant k and unstretched length L0 = 0.75 ft. The maximum distance achieved by the disk from point O is dmax = 1.85 ft while traveling at a speed υ0 = 20 ft/s. Determine the value of k such that the minimum distance between the disk and O is dmin = dmax/2.

Figure P3.70