An electric winch operates on 140 volts [V] and draws 6 amperes [A] of current. The winch has an efficiency of 64%. The winch is used to lift an object that weighs 510 pound-force [lb Subscript f] for 11 seconds [s]. Determine the height the object is lifted to, in units of meters [m].

Explanation:

efficiency = (energy output / energy input)

energy input = ivt where i is current = 6 A, v is volts = 140 and t time = 11 seconds

energy input = 6 × 140 × 11 = 9240 J

energy output = 0.64 × 9240 = 5913.6 J

510 pound-force = 2268.593 N

at height h, potential energy = mgh = 5913.6 J

2268.593 × h = 5913.6

h = 5913.6 / ( 2268.593) = 2.61 m

answer: 500 wph.

explanation: