Water flows at $1\mathrm{.}0$m$/$s through a horizontal pipe with diameter $4\mathrm{.}0$ cm$.$ When the pipe narrows to $2\mathrm{.}0$ cmdiameter:a$)$ What is the new speed of the water?b$)$ If the pressure on the wide end is $4\mathrm{.}5$x$104$ Pa$,$ what is the pressure at the narrow end $($assume the pipe has the same height at both ends$)?$