A small 40-lb block A is attached to the rod BC of negligible mass which is supported at B by a pin and bracket and at C by a spring of constant k = 140 lb/ft. The system can move in a vertical plane and is in equilibrium when the rod is horizontal. The rod is acted upon at C by a periodic force P of magnitude P = Pm sin ωft where Pm = 1.4 lb. Knowing that ωf = 15 rad/s, determine the range of values of b for which the amplitude of vibration of block A exceeds 0.14 in.

Transcribed Image Text:

B 32 in. TOW P=P sin eyt