In dimension of critical velocity v c, of liquid following through a tube are expressed as (ηxρyrz) , where η,ρ and rare the coefficient of viscosity of liquid, density of liquid and radius of the tube respectively, then the values of x, y and z are given by :

νc∝ηxρyrz [L1T-1]∝ [M1L-1T-1]x [M1L-3]yL1z  [L1T-1]∝ [Mx+y][L-x-3y+z][T-x]Taking comparison on both sidesx+y=0, -x-3y+z=1, -x=-1⇒x= 1,y=-1,z=-1ALTERNATE SOLUTION:REYNOLDS NUMBER    R=D v ρη=M0L0T0 V α ηr-1ρ-1  v is critical velocity D = DIAMETER OF the TUBE , r= radius of the tube.