Question

i dont understand bernoulli principal ,i mean why wud velocity increase when pressure is low.

Answer 1

p+pv2/2=constant
that means p and v are inversely proportional,this like x+y=10
when x=8 -->y must be 2 and when y=8-->x must be 2

Answer 2

When a fluid's velocity is higher, it rushes out with a greater speed, creating a vacancy where it leaves. So, a low pressure is created there. and when it is lower, the pressure is higher.