Question

water is being pumped out through a circular pipe whose internal diameter is 7cm. if the flow of water is 72cm per second how many litres of water are being pumped out in one hour ​

Answer 1

Given data : Water is being pumped out through a circular pipe whose internal diameter is 7cm. The flow of water is 72cm per second.

To find : How many litres of water are being pumped out in one hour.

Solution : Let, pipe's shape be cylindrical.

Now, according to given,

Length/height of pipe = 72 cm

Diameter of pipe = 7 cm

Radius of pipe = d/2 = 7/2 cm

Now,

⟹ volume of pipe = π * r² * h

{ Where,

π = 22/7

r = radius

h = height }

⟹ volume of pipe = 22/7 * (7/2)² * 72

⟹ volume of pipe = 22/7 * 49/4 * 72

⟹ volume of pipe = 22 * 7/4 * 72

⟹ volume of pipe = 22 * 7 * 18

⟹ volume of pipe = 154 * 18

⟹ volume of pipe = 2772 cm³

Now, we know that,

⟹ 1 litre = 1000 cm³

Hence,

⟹ water pumped out in one sec through pipe = 2772/1000 = 2.772 litre

Here, we know that,

⟹ 1 hour = 3600 sec

Now,

⟹ water pumped out in one sec through pipe = 2.772 * 3600 = 9979.2 litre

Answer : Hence, 9979.2 litre of water are being pumped out in one hour.