(2)对B、C两点应用伯努利方程 +phe P8+ 由于PcPo, VB -VC PB Po-pg(hg-hc) =R-Pg(h+h)=2.1×104Pa B B B C C ghC P + v + gh = P + v +  2 2 2 1 2 1 P g h h Pa PB P g hB hC 4 0 1 2 0 ( ) 2.1 10 ( ) = − + =  = − −   (2)对B、C两点应用伯努利方程 B C 由于P v = v C=P0