42. A simple machine raises a load 1.66 m when the effort moves 14.8 m. If the efficiency of the system is 81%, what effort is required to lift a 140 kg mass? 43. A five pulley block and tackle is used to lift a 90 kg mass. Neglecting any losses, what effort must be applied if the block and tackle is used normally? 44. What mass can a 6 pulley block and tackle if a 450 N effort is applied and the block is set up so that the effort is applied in a 1) downward direction, and 2) in an upward direction? 45. A 4 pulley block and tackle lifts a 150 kg mass with an effort of 500 N. What is the efficiency of the system? How far will the load rise if the effort moves 3.65 metres? 46. The lever arm of the safety valve shown below is 0.5 m. The distance from the fulcrum to "C" is 10 cm. If the lever arm at "B" has a maximum lift of 4 cm when it is relieving pressure, what is the full lift of the valve? Hint: consider the ratios of the arm, "A - C" to "A - B".