A Pitot tube mounted on an aeroplane contains alcohol and shows a level difference of 50 em. What is the speed of the plane relative to uir? (Density of alcohol `800 kg m^(-3) " density of air " - 1 kgm^(-3) ) `

Explanation

Pitot tube is used to measure speed of aeroplane. Level difference h - 0-5
` " " V_A = ? `
Density of alcohol `= sigma = 800 kg m^(-y) ` Density of air -`rho = 1 kg m ^(-3)`
Applying Bernoulli.s theorem at A and B.
` P_A +(1)/(2) rho v_A^(2) = P_B +(1)/(2) rho v_B^(2)`
But `v_B = 0 ` because its opening is perpendicular to wind and its velocity is brought to zero.
`(1)/(2) rho v_A ^(2) = P_B - P_A `
` (1)/(2)= rho v_A^(2) = h sigma g `
` " "v_A = sqrt( ( 2ghsigma)/(rho))`
`" " = sqrt((2xx0.5 xx 800 xx 9.8)/( 1))`
` " " = 88. 54 ms ^(-1)`