Question

Sir Lost-a-Lot dons his armor and sets out from the castle on his trusty steed (see figure below). Usually, the drawbridge is lowered to a horizontal position so that the end of the bridge rests on the stone ledge. Unfortunately, Lost-a-Lot's squire didn't lower the drawbridge far enough and stopped it at θ = 20.0° above the horizontal. The knight and his horse stop when their combined center of mass is d = 1.10 m from the end of the bridge. The uniform bridge is ℓ = 7.75 m long and has mass 2 300 kg. The lift cable is attached to the bridge 5.00 m from the hinge at the castle end and to a point on the castle wall h = 12.0 m above the bridge. Lost-a-Lot's mass combined with his armor and steed is 1 065 kg. While Lost-a-Lot ponders his next move, the enemy attacks! An incoming projectile breaks off the stone ledge so that the end of the drawbridge can be lowered past the wall where it usually rests. In addition, a fragment of the projectile bounces up and cuts the drawbridge cable! The hinge between the castle wall and the bridge is frictionless, and the bridge swings down freely until it is vertical and smacks into the vertical castle wall below the castle entrance.

(a) How long does Lost-a-Lot stay in contact with the bridge while it swings downward?
  

(b) Find the angular acceleration (magnitude) of the bridge once it starts to move.
in rad/s²

(c) Find the angular speed of the bridge when it strikes the vertical castle wall below the hinge.
rad/s

(d) Find the force exerted by the hinge on the bridge immediately after the cable breaks.

horizontal component:	magnitude	kN
vertical component:	magnitude	kN
	direction

(e) Find the force exerted by the hinge on the bridge immediately before it strikes the castle wall.

horizontal component:	magnitude	kN
vertical component:	magnitude	kN

Answer 1