Water in a canal, `30 d mw i da n d12 d md e e p` , is flowing with a velocity of `20 k mp e rhou rdot` How much area will it irrigate in `30 m in ,` if `9c m` of standing water is desired?

Explanation

depth = `12dm = 1.2m`
width =` 30dm = 3m`
flow velocity = `20((km)/(h)) = 20,000 (m/h)`
time = `30minute = 0.5 hour`
length=distance covered by water in 30 minutes=velocity of water`xx`time=`(20000xx30)/60=10000`m
standing water required = `9cm = 0.09m`
Let the area =` Am^2`
Volume of water flown in 30 minutes`1.2m xx 3m xx 10000`
`=36000m^3`
`volume = A xx 0.09`
`A = 36000/0.09`
` A = 400000 m^2`