Fill in the blanks using the word(s) from the list appended with each statement:

(a) Surface tension of liquids generally . . . with temperatures (increases / decreases)

(b) Viscosity of gases . .. with temperature, whereas viscosity of liquids . . . with temperature (increases / decreases)

(c) For solids with elastic modulus of rigidity, the shearing force is proportional to . . . , while for fluids it is proportional to . .. (shear strain / rate of shear strain)

(d) For a fluid in a steady flow, the increase in flow speed at a constriction follows (conservation of mass / Bernoulli’s principle)

(e) For the model of a plane in a wind tunnel, turbulence occurs at a ... speed for turbulence for an actual plane (greater / smaller)

(a) decreases

Explanation: Surface tension decreases with increase in temperature because cohesive forces in the liquid decrease with increasing molecular thermal activity. As surface tension depends on cohesive forces of the liquid, it's value decreases at higher temperatures.

(b) increases, decreases

Explanation: Usually gases are free flowing in the atmosphere. When temperature increases collisions between the molecules increase and as a result the their free flow is resisted. Resistance to free flow is known as viscosity. Therefore viscosity increases in gases due to increase in temperature.

(c) shear strain, rate of shear strain

Explanation: In solids

Therefore in solids, shear stress is directly proportional to shear strain.

In fluids according to continuum mechanics, in a Newtonian fluid shear stress is directly proportional to rate of shear strain.

(d) Conservation of mass, Bernoulli's principle

Explanation: A steady flowing fluid's increase in flow speed at a constriction depends on both conservation of mass and Bernoulli's principle.

(e) greater

Explanation: For the model of plane in a wind tunnel turbulence occurs at a greater speed than for an actual plane. This is due to the difference in Reynolds's number associated with the planes.