Question

if pump increases pressure then why wont it go back because of pressure difference?

Answer 1

Velocity is NOT inversely proportional to pressure; FLUID VELOCITY is inversely proportional to FLUID PRESSURE. This is because if the particles have higher velocity in a given direction, then the velocity vector at the other directions will be reduced. In this case the particles’ component of velocity in the direction of flow increases and so the velocities in the other directions decreases. The particles thus collide the walls or other particles at a lower speed which is the cause of the inverse relationship between the FLUID VELOCITY and PRESSURE OF THE FLUID. Note, the velocity of the particles and the fluid velocity are two different things.