Question: A two-dimensional, unsteady velocity field is given by u=9x(1+t) and v=9y(-1+t) where u is the x-velocity component and v the y-velocity component. Find x(t) and y(t) if x=x0 and y=y0 at t=0. Do the velocity components represent a Eulerian or a Lagrangian description?

Given Answer: Eulerian

Please show step-by-step solution, explicitly state the theory or equation used for calculations.