Use dimensional analysis to determine the pressure, P, in the pipe to within a dimen- sionless multiplicative constant of order 1.(Hint: P may depend on another physical variable besides A and R.) Using your result from part (a), reexpress your answer in a form that involves v. By what factor does P increase when v is doubled?

1 answer

LOL, again ?
R = A V = L^2 L/T
P = F/A = m L/T^2 / L^2
P = m L/ (T^2L^2)
m = rho L^3

P = rho L^3 /(T^2 L)

P = rho L^2/T^2 = rho v^2

4

by the way this does not give us the sign and rho is M/L^3 but is constant in the usual incompressible fluid problem