10.设流体的流速为v=(xy5,0,25x2),求穿过柱面x2+y2=a2(-h≤ z≤h)外测的流量10．设流体的流速为v = (xy5 , 0, z5x x )，求穿过柱面x 2 + y 2 = a 2 (−h ≤ z ≤ h)外测的流量． 6