7. In a stream of glycerine in motion, at a certain point the velocity gradient is 0.25 metre per sec per metre. The mass density of fluid is 1268.4 kg per cubic metre and kinematic viscosity is 6.30 x 10 squar per second. Calculate the shear stress at the point. t & Find the kinematic viscosity of an oil having density 980 kg/m when at a certain point in the oil, the [Ans. 0.2 N/m stress is 0.25 Nm and velocity gradient is 0.3/s. Ans. 0.000849- or 8.49 stokes 9. Determine the specific gravity of a fluid having viscosity 0.07 poise and kinematic viscosity 0.042 stokes [Ans. 1.667] 10. Determine the viscosity of a liquid having kinematic viscosity 6 stokes and specific gravity 2.0. [Ans. 11.99 poise] 11. fthe velocity distribution of a fluid over a plate is given by u (3/4) y-y, where u is the velocity in metre per second at a distance of y metres above the plate, determine the shear stress at y 0.15 metre, Take [Ans. 3.825 x 10 kefhu] 12. An oil of viscosity 5 poise is used for lubrication between a shaft and sleeve. The diameter of shaft is 05 m and it rotates at 200 r.p.m. Calculate the power lost in the oil for a sleeve length of 100 mm. The [Ans. 2.15 kW] dynamic viscosity of the fluid as 8.5 x 10 kg-sechm. thickness of the oil film is 1.0 mm. 13. The velocity distribution over a plate is given by u = y-y in which u is the velocity in m/sec at a distance of y m above the plate. Determine the shear stress at y 0,0.1 and 0.2 m. Take p = 6 poise. [Ans. 0.4, 0.028 and 0.159 N/m) mal 14. In question 13, find the distance in metres above the plate, at which the shear stress is zero. [Ans. 0.333 m) 15. The velocity profile of a viscous fluid over a plate is parabolic with vertex 20 cm from the plate, where the velocity is 120 cm/s. Calculate the velocity gradient and shear stress at distances of 0, 5 and 15 cm from the plate, given the viscosity of the fluid 6 poise. [Ans. 12/s, 7.18 N/m; 9/s, 5.385 N/m²; 3/s, 1.795 N/m') 16. The weight of a gas is given as 17.658 Ñ/m at 30°C and at an absolute pressure of 29.43 N/cm². Deter- 1.8 kg 539.55 N m kg K 17. A cylinder of 0.9 m in volume contains air at 0C and 39.24 N/cm² absolute pressure. The air is compressed to 0.45 m. Find () the pressure inside the cylinder assuming isothermal process, mine the gas constant and also the density of the gas. Ans.- m (i) pressure and temperature assuming adiabatic process. Take k = 1.4 for air. [Ans. (1) 78.48 N/cm, () 103.5 N/m, 140°C] 18. Calculate the pressure exerted by 4 kg mass of nitrogen gas at a temperature of 15°C if the volume is 0.35 m. Molecular weight of nitrogen is 28. 19. The pressure of a liquid is increased from 60 N/cm to 100 N/cm and volume decreases by 0.2 per cent. Determine the bulk modulus of clasticity. 20. Determine the bulk modulus of elasticity of a fluid which is compressed in a cylinder from a volume of 0.009 m at 70 Nicm pressure to a volume of 0.0085 m at 270 N/cm pressure. [Ans. 3.6 x 10 Nem 21. The surface tension of water in contact with air at 20°C is given as 0.0716 N/m. The pressure inside a droplet of water is to be 0.0147 N/cm² greater than the outside pressure, calculate the diameter of the [Ans. 97.8 N/em) (Ans. 2 x 10 Nem] droplet of water. 22. Find the surface tension in a soap bubble of 30 mm diameter when the inside pressure is 1.962 N/m" above atmosphere. n The surface lension of water in contact with air is given as 0.0725 N/m. The pressure outside the droplet of [Ans. 1.94 mm) (Ans. 0.00735 Nm] water of diameter 0.02 mm is atmospheric Calculate the pressure within the droplet of cm water. [Ans. 11.77 N/cm)