A gas flows along the $x$ axis with a speed of $V=5 x \mathrm{m} / \mathrm{s}$ and
eressure of $p=10 x^{2} \mathrm{N} / \mathrm{m}^{2},$ where $x$ is in meters.
(a) Determine the time rate of change of pressure at the fixed location $x=1$
(b) Determine the time rate of change of pressure for a fluid particle flowing past $x=1 .$ (c) Explain without using any equations why the answers to parts (a) and (b) are different.