The actual mechanical advantage of a pulley is 2. The pulley has 3 supporting strings. What is the efficiency of the pulley?

A. [tex]$100 \%$[/tex]
B. [tex]$50 \%$[/tex]
C. [tex]$66 \%$[/tex]
D. [tex]$150 \%$[/tex]



Answer :

Sure, let's solve the problem step-by-step.

1. First, understand and note the given data:
- The actual mechanical advantage (AMA) of the pulley is 2.
- There are 3 supporting strings, which gives the ideal mechanical advantage (IMA) as 3.

2. Recall the formula to calculate the efficiency of a pulley:
[tex]\[ \text{Efficiency} = \left(\frac{\text{Actual Mechanical Advantage (AMA)}}{\text{Ideal Mechanical Advantage (IMA)}}\right) \times 100 \][/tex]

3. Substitute the given values into the formula:
[tex]\[ \text{Efficiency} = \left(\frac{2}{3}\right) \times 100 \][/tex]

4. Perform the division and multiplication to find the efficiency:
[tex]\[ \frac{2}{3} \approx 0.6666666666666666 \][/tex]
[tex]\[ 0.6666666666666666 \times 100 = 66.66666666666666 \][/tex]

5. Therefore, the efficiency of the pulley is:
[tex]\[ 66 \% \][/tex]

So, the correct answer from the given options is:
[tex]\[ \boxed{66\%} \][/tex]