Water in a canal, 6 m wide and 1.5 m deep, is flowing with a speed of 10 km/h. How much area will it irrigate in 30 minutes, if 8 cm of standing water is needed?
It is given that the canal is the shape of a cuboid with dimensions as:
Breadth (b) = 6 m and Height (h) = 1.5 m
The speed of canal = 10 km/hr
Length of canal covered in 1 hour = 10 km
Length of canal covered in 60 minutes = 10 km
Length of canal covered in 1 min = (1/60) x 10 km
Length of canal covered in 30 min (l) = (30/60) x 10
= 5km = 5000 m
We know that the canal is cuboidal in shape.
Volume of canal = l x b x h
= 5000x6x1.5 m3
= 45000 m3
Volume of water in canal = Volume of area irrigated
= Area irrigated x Height
Area irrigated = 56.25 hectares
∴ Volume of canal = l x b x h
45000 = Area irrigatedx8 cm
45000 = Area irrigated x (8/100)m
Area irrigated = 562500 m2
= 56.25 hectares.