However, at the same time I met the pulley the barrel of bricks hit the ground and tipped over. The result was that some 160 kg of bricks spilt onto the ground. Now devoid of some bricks, the barrel weighed approximately 60 kg. I refer you again to my weight in Block #11. As you might imagine, I began a rapid descent down the side of the building. In the vicinity of the third floor, I met the barrel coming up ... one leg on the outside of the barrel and one on the inside. This accounts for the two fractured ankles, broken tooth, and the severe lacerations of my legs and lower body (not to mention the bruised groin).
The encounter with the barrel seemed to slow it up enough to lessen my injuries when I fell onto the pile of bricks and fortunately only three vertebrae were cracked. Unfortunately, when the barrel hit the pulley at the top of the building, the bottom fell out and the remaining 40 kg of bricks rained down on me which explains the multiple bruises and lacerations on my upper body. I am sorry to report, however, that as I lay there on the pile of bricks in pain, unable to move and watching the empty barrel six stories above me, I again lost my composure and presence of mind and let go of the rope. The barrel then began a rapid descent towards the ground and myself. Fortunately for me I lapsed into unconsciousness. However, the paramedics assure me that this would account for the four cracked ribs, broken nose, and dislocated shoulder mentioned in Section II of the accident form.
Sincerely
J. Atwood, Master Bricklayer
ASSIGNMENT
1. For the two situations where the brick-layer and barrel are both in motion (a) draw complete free-body diagrams and (b) determine the acceleration of each and the tension on the rope, assuming friction to be negligible. Remember to use g = 9.8 N/kg.
2. What was the speed of the bricklayer relative to the barrel full of bricks when they met on the first collision. You can assume that one "story" on this building is 5.0 m? Be sure to use relative velocities to prove the speed of the bricklayer relative to the barrel.