Problem

The figure shows the cross section of a garage door with length L = 9 ft and weight W = 17...

The figure shows the cross section of a garage door with length L = 9 ft and weight W = 175 lb. At the ends A and B there are rollers of negligible mass constrained to move in a vertical and a horizontal guide, respectively. The door’s motion is assisted by two springs (only one spring is shown), each with constant k = 9.05 lb/ft. If thedoor is released from rest when horizontal and the spring is stretched 4 in., neglecting friction, and modeling the door as a uniform thin plate, determine the speed with which B strikes the left end of the horizontal guide.