Question

An ideal block and tackle system of $5$ pulleys consist of $3$ pulleys in the upper block and $2$ pulleys in the lower block. If the load is raised by $1\text{m}$, through what distance will effort move?

• A. $5\text{m}$
• B. $7\text{m}$
• C. $1\text{m}$
• D. $3\text{m}$

Answer 1

The correct option is A $5\text{m}$

As there are $5$ strings in the block and tackle system,

Velocity ratio of the system = $\text{VR}$ = $\text{n}$ = $5$ [$\because$ System is ideal]

Also $d_L$ = $1\text{m}$

$\text{V.R}=\frac{d_E}{d_L},$ where $d_E$ and $d_L$ are displacement of effort and load respectively.

$d_E=5\times d_L=5\times 1$ = $5\text{m}$