Question

Water level in a well was 20m below ground level. During rainy season, rainwater collected in different water tanks was drained into the well and the water level rise 5 m above the previous level. The wall of the well is 1m 20cm high and a pulley affixed at a height of 80 cm. Raghu wants to draw water from the well. Find the minimum length of the rope that he can use.

Answer 1

17 m

Explanation:

As shown in the figure,
`A_0-B_0` is the ground level,
`A_1-B_1` is the old level of water which was at 20 m below ground level,
`A_2-B_2` is the new level of water which is 5m above of old level. The height of wall of the well, 1.20 m, and the the pelly at 80 cm =0.80 m, has been shown too.

The minimum length of the rope is equal to the distance between the pully and the new water level, indicated by the length
`L_0` in the figure.

So,
`L_0= 20-5+1.20+0.80= 17m`

Hence, Raghu must use a rope having the minimum length 17 m to draw water from the well.