You and two friends, Sam and Todd, are rock climbing in the wilderness. Todd is stranded at the bottom of a cliff that is 60 feet high. You and Sam are at the top of the cliff trying to figure out how to get him back to the top. The cliff is a shear vertical face with no handholds and so it is impossible to climb up or down. The rock climbing gear that you have on hand includes two single pulleys, a block and tackle and 200 feet of rope. There is a boulder at the edge of the cliff where you can anchor a pulley or block. The plan is for Sam to lower you down the cliff while he supports the rope at the top. You have a mass of 75 kg and Sam can provide a maximum force of 300 N to support the rope. Now you have to decide how to setup your equipment to be able to safely get down the cliff and bring both you and Todd back up.
1. (10 points) Sam suggests using the two single pulleys as shown below in Figure 1.
a) Do you have enough rope for this?
b) Will Sam be able to safely lower you down the cliff using this setup?
c) Will Sam be able to safely lift both you and Todd back to the top using this setup? Todd also has a mass of 75 kg and Sam can pull on the rope with the same 300 N force.
2. (8 points) You instead propose using the block and tackle as shown below in Figure 2.
a) Do you have enough rope for this?
b) Will Sam be able to safely lift both you and Todd back to the top using this setup?
c) After looking carefully at the block and tackle you find that it is damaged and cannot be used.
What can you do instead to safely rescue Todd and is it feasible in this case?  

Sam's Force (Assume Rope Vertical) Figure 1 - Single Pulleys Anchor To Boulder Single Pulleys Tie To Climbers Figure 2 - Block & Sam's Force (Assume Rope Vertical) Tie To Climbers (You/Todd) 20