a 12-lb collar is attached to a spring anchored at point C and can slide on a friction-less rod forming a 30 degree angle with the vertical. The spring has constant k and is unstretched when the collar is at A. Knowing that the collar is releasted from rest at A, develop an equation to determine the velocity of the collar at point B for any given value of k (k-range is 0.1-2.0 lb/in)