A chain hoist furnished with 120 hp lifts to a height of 40 ft in 20 sec.
Not enough data. What weight are you lifting ?
let?s get coherent units1 hp=0.7453 kw and 40 feet = 12.192m The power used = weight lifted*velocity As you don?t state the weight there is information missing in any efficiency = weight*velocity /120*745.3 Units weight Newtons,Power watt ,height meter and time sec.
