Answer:
The efficiency of the pulley, % Efficiency is [tex]69.\overline 4[/tex]%
Explanation:
The given parameters in the question are;
The mass of the actress playing Peter Pan (the pulley load) = 125 lb
The force applied to hoist the actress by the stage hand = 30 lbs
The actual mechanical advantage, AMA = Load/Force applied
Therefore, the AMA of the pulley = 125 lbs/(30 lbs) = 25/6 = [tex]4.1 \overline 6[/tex]
The pulley's Ideal mechanical advantage, IMA = The number of stands in the pulley = 6
The efficiency of a pulley is given by the following formula;
[tex]\% \ Efficiency = \dfrac{AMA}{IMA} \times 100[/tex]
Where
AMA = The actual mechanical advantage
IMA = The ideal mechanical advantage
Therefore, the efficiency of the pulley, % Efficiency, is given by plugging in the values of the AMA and the IMA in the efficiency formula as follows;
[tex]\% \ Efficiency = \dfrac{\dfrac{25}{6} }{6} \times 100 = \dfrac{625}{9}\% = 69.\overline 4\%[/tex]
The efficiency of the pulley, % Efficiency = [tex]69.\overline 4[/tex]%
