At a sudden contraction in a pipe the diameter changes fromD1toD2. The pressure drop,Δp, which develops across the contraction is a function ofD1andD2, as well as the velocity,V, in the larger pipe, and the fluid density, rho, and viscosity,μ. UseD1,V, andμas repeating variables to determine a suitable set of dimensionless parameters. Why would it be incorrect to include the velocity in the smaller pipe as an additional variable?