Water in a canal, 6m wide and 1.5m deep, is flowing with a speed of 10 km/h. How much area will it irrigate in 30 minutes ,if 8cm of standing water is needed?
Answers
Answer: 100 minutes ( 0.6 hours)
Step-by-step explanation:
Depth of canal = 1.5 m
Flow rate of water = 10 km/h
Distance= speed × time
Distance traveled by the water in 30 minutes = 1000×1/2 = 500m
Amount of water irrigated in 20 minutes
= 6 x 1.5 x 500 m3
= 4500 m3
Area irrigated by this water if 8 cm standing water is desired i.e 8cm = 0.08 m
= 4500 / 0. 08 m2
= 56250 m2
= 0.05625 km2.
2)
Given that diameter of the cylindrical tank = 10 m
Radius of the cylindrical tank (r) = 5 m
Height of the cylindrical tank (H) = 2 m
Volume of cylindrical tank = πr2H
= π × 52 × 2
= 50 π m3
Internal Diameter of the pipe (d) = 20 cm
Internal Radius of the pipe (r) = 10 cm = (1/10) = 0.1 m
Rate of flow of water = 3 km /hr = 3000 m/ hr.
So that volume of water that flows in t hours from the pipe = Area of cross section of pipe × speed × time
= π(1/10)2 x 3000 x t = 30πt m3
∴ Volume of water that flows from the pipe into the tank in "t" hours = volume of the tank
⇒ 30 π t = 50 π
⇒ 30 t = 50
⇒ t = 50 / 30 hrs
⇒ t = 5 / 3 hrs
= 1 hr 40 min
= 100 minutes.