A fluid is flowing through a rubber hose.
If you squeeze the hose in one place to half its original diameter, what happens to the speed of the fluid at that place?
What would you have to do to the hose's cross-sectional area to make the fluid's speed five times slower than at the rest of the hose?
What would you have to do to the diameter of the hose to make the fluid's speed five times faster than at the rest of the hose?