P$30.($a$)$ Calculate the absolute pressure at an ocean depth of $1000$ m$.$ Assume

the density of seawater is $1030$ kg$/$m and the air above exerts a pressure of$3$

$101,325$ N$/$m $.($b$)$ At this depth, what is the buoyant force on a spherical$2$

submarine having a diameter of $5\mathrm{.}00$ m