A Blackhawk helicopter is winching up an injured soldier from a danger zone.The soldier and his kit have a mass of 150 kg and are pulled up 50 m in the air at a steady rate.If it takes 30 s to pull the soldier up,how much power has been used by the helicopter's 65% efficient winch engine?

Question

Quizplus · Accepted Answer

First, we need to calculate the work done by the winch engine in lifting the soldier and his kit:
Work = Force x Distance
The force required to lift the soldier and his kit is equal to their combined mass multiplied by the acceleration due to gravity (9.81 m/s^2):
Force = 150 kg x 9.81 m/s^2
Force = 1471.5 N

The distance lifted is 50 m, so:
Work = 1471.5 N x 50 m
Work = 73,575 J

Next, we need to calculate the power output of the winch engine, taking into account its efficiency:
Power output = Work / Time / Efficiency
Time = 30 s
Efficiency = 65% = 0.65

Power output = 73,575 J / 30 s / 0.65
Power output = 3,817.8 W or 3.8 kW (rounded to one decimal place)

Therefore, the answer is B) 3.8 kW.

A Blackhawk Helicopter Is Winching Up an Injured Soldier from a Danger