The figure shows the cross section of a garage door with length L = 2.5 m and mass m = 90...

The figure shows the cross section of a garage door with length L = 2.5 m and mass m = 90 kg. 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 counterweights (only one counterweight is shown), each of mass mC = 42.5 kg. If the door is released from rest when horizontal, 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.

Figure P8.45