A cylindrical pipe has inner radius of 3.5 cm and water flows through it at 154 litres per minute. Find the rate of flow in kilometres per hour.
Hi,
Radius of cylindrical pipe = 3.5 cm
Volume of water flows in 1 min = 154 l
∴ Volume of water flows in 1 hour = 154 × 60 × 1000 cm3 ….....(1)
Let l be the distance covered by water in 1 hour
Volume of water that covers the diameter of 1 hour = πr2 l .....(2)
From (1) and (2)
⇒ πr2 l = 154× 60 × 1000
⇒ (22/7) x (3.5)2 x l =154 × 60 × 1000
⇒ l =240000
l = 240000 cm
l =2.4 km
i.e. distance covered by water in 1 hr is 2.4 km
∴ Rate of flow of water =2.4 km/hr.