35. Shown below is a lever arm safety valve. If the relief pressure desired is 100 kPa, what mass W, in kilograms, must be attached to the lever end? The distance A - B is 0.45 metres and A - C is 10 cm. The valve disc area on which the pressure is applied is 19.635 cm. The mass of the lever arm and the valve disc is not considered for this example. w 36. Shown below is a lever arm safety valve. If a force of 700 N, at "C", is required to keep the valve shut, what mass "W" must be attached to the lever end? The distance A - B is 0.5 metres and A - C is 13.5 cm. The mass of the lever arm and the valve disc is not considered for this example. 57. How much potential energy is transformed into kinetic energy if a ball with a mass of 0.24 kg is drops from a height of 2.33 m to a height of 0.667 metres? 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". 58. A ball with a mass of 0.5 kg is uniformly accelerated from rest at a rate of 1.7 m/s. What is the kinetic energy of the ball after it has accelerated a distance of 12 metres?