A slender tube is inserted vertically into the middle of a steady water stream such that its open end directly faces the oncoming flow. The water column inside the tube rises several centimetres above the free surface of the surrounding stream.
(i) Define a stagnation point in a fluid flow.
(ii) Distinguish between static pressure and dynamic pressure in the context of this arrangement.
(iii) Explain, with reasons, why the velocity of water at the entry of the tube is zero even though the surrounding fluid is moving with a finite speed.