An 0.8-lb ball is connected to a paddle by means of an elastic cord AB of constant k = 5 l...

An 0.8-lb ball is connected to a paddle by means of an elastic cord AB of constant k = 5 lb/ft. Knowing that the paddle is moved vertically according to the relation δ = δm sin wft, where δm = 8 in., determine the maximum allowable circular frequency wf if the cord is not to become slack.