Question

The cross-section of a pipe is 42 cm² and water is pouring out of it at the rate of 1.25 m per sec. If the pipe remains full, find the number of litres discharged per minute.

Answer 1

Given: Cross‑sectional area = 42 cm²; water speed = 1.25 m/s.

Step-wise calculation:

1. Convert speed to cm/s:

1.25 m/s = 1.25 × 100

= 125 cm/s

2. Volume flow per second

 = Area × Speed

= 42 cm² × 125 cm/s

= 5250 cm³/s

3. Convert to litres:

1000 cm³ = 1 litre

5250 cm³/s = 5250 ÷ 1000

= 5.25 L/s

4. Convert to litres per minute:

5.25 L/s × 60 s/min

= 315 L/min

315 litres are discharged per minute.