A chain hoist furnished with 120 horse power lifts 1100 lb. to a height of 40 ft. in 20 sec.
power developed by this machine is given by........ change in potential energy in unit time is the power .......... = mgh/t = 1100*10*40/20; = 22000 in the unit of power in FPS system.......... convert this into horsepower...... and this is your output...... the input is 120 HP; so the efficiency is (the answer you got) / 120 * 100%;
Efficiency = Output/Input Here the machine lifts 1100 lb. to ht. of 40 ft in 20sec So its output power = mgh/t = 1100*9.8*40/20 = something Now divide that something by 120 HP. Multiply the ratio by 100 if you require efficiency in percentage.....
