4A Power Engineering - Unit 1 - Elementary Mechanics and Dynamics 100% Solved

4A Power Engineering - Unit 1 - Elementary Mechanics and Dynamics 100% Solved (4-011-1.17) In simple machines, 'efficiency' is: Work input x work output Work input / work output Work output + work input Work output / work input Work output / work input (4-016-2.5) What is the factor of safety for a steel hanger that has an ultimate strength of 70 000N/cm2 while supporting a load of 87 500N. The hanger has a cross-sectional area of 5cm2. 1.25 6.25 4 8 4 (4-011-1.12) A lifting machine requires an effort of 400N to raise a mass of 100kg. If the mass rises 4m while the effort moves 12m, find the efficiency of the machine. 93% 82% 80% 75% 82% (4-017-1.3) A pulley of diameter 2.6m rotates at 107 r/min and drives another pulley at 259 r/min. What is the diameter of the driven pulley? 1.07 m 6.3 m 0.93 m 3.54 m 1.07 m (4-017-2.1) A gear wheel with 85 teeth rotates at 6500 r/min and drives another gear at 9,866 r/min. How many teeth does the driven gear have? 56 129 76 85 56 (4-009-2.12) A hydraulic piston with an area of 0.05 m2 is being moved with a force of 150N. What pressure is being exerted on the piston?