Question

3.
A rectangular reservoir is 120 m long and 75 m wide find the speed of water flowing into it
through a square pipe of 20 cm side such that water rises by 1.2 m in 9 hours.

Answer 1

Given that 120 m long and 75 m wide find the speed of water:

Step-by-step explanation:

• Volume of water accumulated in the reservoir in 9 hours = (120×75×1.2) m^3.
• Let the speed of the water be v km/hr.
• Water in the pipe forms a cuboid of width  20/100 = 1/5m, height = 20/100 =1/5.

• Length of the water cuboid formed in 9 hours = 9 v km = 9000 v meters.
• Volume of water accumulated in the reservoir in 9 hours.

• V = 9000v×1/5 × 1/5 m^3 = 360m^3
• 360m^3.v = 120× 75 × 1.2 ⇒ v = 30km/hr.

• Water must flow at the speed of 30 km/hr. into the reservoir.