Đáp án:
p=265258,2385pa
Giải thích các bước giải:
\(\begin{array}{l}
\frac{{{F_1}}}{{{F_2}}} = \frac{{{s_1}}}{{{s_2}}} = \frac{{\pi r_1^2}}{{\pi r_2^2}} = \frac{{r_1^2}}{{r_2^2}}\\
{F_1} = \frac{{r_1^2}}{{r_2^2}}{F_2} = \frac{{{4^2}}}{{{{12}^2}}}.12000 = \frac{{4000}}{3}N\\
p = \frac{{{F_1}}}{{{s_1}}} = \frac{{{F_1}}}{{\pi r_1^2}} = \frac{{\frac{{4000}}{3}}}{{\pi .0,{{04}^2}}} = 265258,2385pa
\end{array}\)