Question

If a well is 210 m deep and 10 m additional rope is required for loops and knots to draw water from the well. If the rope runs on a pulley of 21 cm diameter how much times will the pulley rotate to reach the well?​

Answer 1

Answer:

Circumference of Pulley

$= 2\pi \: d = 2 \times \frac{22}{7} \times 21 = 132 \: cm$

Total length of rope = 210+10 = 220 m

No. of rotations,

$\frac{220 \times 100}{132} = 166.66$

Answer 2

Circumference of Pulley

$= 2\pi \: d = 2 \times \frac{22}{7} \times 21 = 132 \: cm$

Total length of rope = 210+10 = 220 m

No. of rotations,

$\frac{220 \times 100}{132} = 166.66$