1-35. In the arrangement of figure 1K the purpose of block A is to 1. increase  the  mechanical advantage of the block 2. change the direction of the applied  force 3. hold up block B 4. act as a runner for block B 1–36. A luff tackle is a block and tackle consisting of a 1-38. For which requirement will it be to your advantage to rig a yard to a stay tackle if each tackle has a theoretical  mechanical  advantage  of two? 1. A  theoretical  mechanical advantage of 4 2. A change in the direction of pull  for  convenience 3. A heavy crate to be lifted to the other side of a low fence 4. An increase in speed 1. fixed double block and a movable  single  block 2. movable  double  block  and  a fixed single block 3. fixed single block and a movable  single  block 4. fixed triple block and a 1–39. The  overall  mechanical  advantage  in movable  double  block figure 1L is about Information  for  questions  1-37  and o 1–38: Alone  you’re  going  to  hoist a 600–pound load to a height of 36 feet. You can pull 160 pounds’ worth. You have to use a fixed block fastened to a beam above  you. You have a movable block attached to the pad eye of the load. 1–37. What  minimum  mechanical  advantage must  the  block  and  tackle  provide? 1. One 2. Two 3. Three 4. Four 1. five 2. six 3. eight 4. twelve 1-40. You are using a differential pulley to lift a load of 2,400 pounds. Fifty pounds of effort are required to overcome the frictional resistance of the pulley. What force is necessary to lift the load if the theoretical mechanical advantage of the pulley is 24? 1. 50 lb 2. 100 lb 3. 150 lb 4. 200 lb 6