91Ó°ÊÓ

[fluid mechanics] The velocity, \(v\), of a fluid through a pipe is given by $$ v=\frac{1}{40}\left(400-x^{2}\right) \quad-20 \leq x \leq 20 $$ where \(x\) is the distance from the central axis. Sketch the graph of \(v\) against \(x\).

[fluid mechanics] The streamlines of a fluid flow are given by $$ y=3 x+c $$ where \(c\) is a constant. On the same axes, sketch the graphs for \(c=-10,-5,-1,0,1,5\) and 10