Question

A women draws water from a well using a fixed pulley. The mass of the bucket and water together is $6kg$. The force applied by the women is $70N$. The mechanical advantage is

• A. $0.96$
• B. $0.86$
• C. $0.76$
• D. $0.66$

Answer 1

The correct option is B

$0.86$

Step 1: Given data,

The force applied by the woman is $70N$
The mass of bucket and water together is $6kg$

Step 2: Find the mechanical advantage,

As we know, $w=mg$

Here, $w$ represents the weight, $m$ represents the mass, and $g$ represents the acceleration due to gravity,

Taking acceleration due to gravity as $10m/s^2$

So, the total weight is,

$$\begin{gathered} w=6kg\times 10m/s^2 \\ w=60N \end{gathered}$$

Mechanical advantage $MA=\frac{weight}{forceapplied}$

Here weight is $60N$ and force applied is $70N$

So,

$$\begin{gathered} MA=\frac{60N}{70N} \\ =0.857 \end{gathered}$$

On rounding the above expression we get a mechanical advantage $0.86$.

Hence, option (B) is correct.