A fluid flow is represented by the velocity field $$\overrightarrow V = ax\,\overrightarrow i + ay\,\overrightarrow j ,$$ where a constant . The equation of stream line passing through a point $$(1, 2)$$ is

Circulation is defined as line integral of tangential component of velocity about a _________ (fill in the blank)

Streamlines, path lines and streak lines are virtually identical for

Existence of velocity potential implies that