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

question 56

Multiple Choice

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?

• A)2.5 kW
• B)3.8 kW
• C)1.6 kW
• D)4.1 kW
• E)3.2 kW

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Definitions:

Dependent Variable

The variable in an experiment that is expected to change or respond as a result of manipulations of the independent variable.

Manipulates

To control or influence a person, situation, or system cleverly, unfairly, or unscrupulously, often to gain an advantage.

Independent Variable

In an experiment, the variable that is manipulated to observe its effect on a dependent variable.

Treatment Variable

A variable manipulated by researchers in an experiment to determine its effect on an outcome measure; also known as the independent variable.