Question

Fluid

7-The surface tension is phenomenon due to (a) Cohesion (b) Viscous force (c) Adhesion between liquid and solid molecules (d) Difference between the forces of adhesion and cohesion 8-The discharge 100 ft/min is equal to (a) 41.23 LUs (b) 45.23 L/s (c) 47.23 Ls (d) 49.23 L/s 9-Specific gravity is the relation between (a) the density of the fluid of specific material to the density of water at 4 °C (b) the density of the fluid of specific material to the density of water at 40 °C (c) the density of the fluid of specific material to the density of water at 4 °P (d) the density of the fluid of specific material to the density of water at 40 °F 10- A Newtonian fluid is the one which (a) has pressure of 1 newtons/m2 (b) has specific weight of 1 newtons/m3 (c) has a linear relationship between the shear stress and the velocity gradient (d) has a high viscosity

Answer 1

7.The surface tension is the phenomenon due to cohesion.(option A)

Cohesive forces between molecules in a liquid are shared with all neighboring atoms. Those particles which are  on the surface have no neighboring atoms above, and they exhibit stronger attractive forces upon their nearest neighbors on the surface. This enhancement of the intermolecular attractive forces at the surface is called surface tension.

8.1 ft³=28.3168 litre

100 ft³=28.3168*100=2831.68

1 min=60 sec

so 100 ft³/min=2831.68/60=47.2 L/s(option c)

9.option A(it is generally calculated at 4 degree celcius)

10.Newtonian fluid is the fluid which obeys newton's law.which states that the shear stress is directly proportional to velocity gradient.so option c is correct i.e newtonian fluid has a linear relationship between shear stress and velocity gradient.