Can a frictional force act on a block on an inclined plane even when the block is not moving?
Yes it can act to balance out gravitational force along the inclined plane's direction.
What does the stream function represent apart from velocity?
The stream function represents the volumetric flow rate apart from the velocity.
Which test does not prove that two triangles are congruent? SSS, SAS, ASA or AAA.
AAA test does not prove that triangles are congruent. AAA test proves similarity.