What is the force required (in Newtons) to hold a spherical balloon stationary in water at a depth of H from the air-water interface? The balloon is of radius 0.1 m and is filled with air ?

Related Mcqs:

1. The location of centre of pressure, which defines the point of application of the total pressure force on the surface, can be calculated by applying the principle of moments according to which “sum of the moment of the resultant force about an axis is equal to the sum of the components about the same axis”. The centre of pressure of a rectangular surface (of width ‘w’) immersed vertically in a static mass of fluid is at a depth of (where, y = depth of the liquid) ?

   A. 1/(y/3)
   B. 2y/3
   C. 1/(y/4)
   D. 3y/4

2. In Newton’s law range, the drag co-efficient for the motion of spherical particle in a stationary fluid is___________________?

   A. 0.44
   B. 0.044
   C. 4.4
   D. 44

3. Drag co-efficient for motion of spherical particles in a stationary fluid in the stoke’s law range is_________________?

   A. 24/NRe,P
   B. 16/NRe,P
   C. 64/NRe,P
   D. 48/NRe,P

4. The terminal velocity of a solid spherical particle falling through a stationary fluid mass in the Stoke’s law range is proportional to the_____________________?

   A. Inverse of fluid viscosity
   B. Square of particle size
   C. Difference in the densities of the particle & fluid
   D. All A., B. and C.

5. The ratio of the wall drag to the form drag in the Stoke’s law range (for motion of spherical particles in a stationary fluid) is__________________?

   A. 0.5
   B. 1
   C. 2
   D. 0.33

6. For motion of spherical particles in a stationary fluid, the drag co-efficient in hindered settling compared to that in free settling is _______________?

   A. More
   B. Less
   C. Equal
   D. More or less, depending on the type of particle

7. In the Newton’s law range, the terminal velocity of a solid spherical particle falling through a stationary fluid mass is ______________ the fluid viscosity?

   A. Directly proportional to
   B. Inversely proportional to
   C. Inversely proportional to the square root of
   D. Independent of

8. In Newton’s law range, the terminal velocity of a solid spherical particle falling through a stationary fluid mass varies as the ______________ of its diameter?

   A. Inverse
   B. Square root
   C. Second power
   D. First power

9. Hydraulic mean radius for flow through packed bed of spherical particle of size, ‘Dp, with porosity ‘ε’ is________________?

   A. (Dp/6) (ε/1- ε)
   B. (Dp/6) (1- ε/ε)
   C. ⅔Dp (1- ε/ε)
   D. ⅔Dp (ε/1- ε)

10. The lift of a balloon is_________________?

    A. Increased, as it rises to a higher altitude
    B. Due to the weight of the atmospheric air, that it displaces
    C. Not dependent on the temperature of the atmosphere
    D. None of these