Water is flowing through a horizontal tube of length 0.25 m and radius ` 4xx 10 ^(-4)` m under a constant pressure head of 0.2 m of water, at the rate of `5 xx 10 ^(-6) m^(3)` per minutre . Calculate the coefficient of visosity of water. Density of water = 1000 kg `m^(-3)`

Explanation

` " " l = 0.25 m, r- 4 xx 10 ^(-4) m `
` " " P= h rho g =0.2 m " of water " = 0.2 xx 10 ^(3) xx 9.8 Pa`
Volume ` V = 5 xx 10 ^(-6) m^(3)`
` " " t= ` one minute = 60s
` eta = ? `
` Q = ( V)/(t) = (pi P r^(4))/( 8 eta l) `
` eta = ( pi h rho g r^(4) t)/( gl V) `
` = (3.14 xx 0.2 xx 10 ^(-3) xx 9.8 xx ( 4 xx 10 ^(-4) ) ^(4) xx 60 )/( 8 xx 0.25 xx 5 xx 10 ^(-6)) `
`= 0 .000945 N s m^(-2)`