Buoyancy and Floatation MCQ – Fluid Mechanics

41. A merchant ship has metacentric height of 2.7 m. After unl0ading it increased to 3.6 m. The ratio of periodic times before and after unloading the cargo ship if radius of gyration is not altered is

  1. 1
  2. 0.75
  3. $\sqrt{\frac{3}{4}}$
  4. $\sqrt{\frac{4}{3}}$
Answer
Answer. d

42. A 10 cm side cube weighing 5 N is immersed in a liquid of relative density 0.8 contained in a rectangular tank of cross-sectional area 15cm × 15 cm. If the tank contained liquid to a height of 8cm before the immersion. The buoyant force on the cube is

  1. 5000 N
  2. 10 N
  3. zero
  4. 5 N
Answer
Answer. d

43. An iceberg floats in sea water. If the specific gravity of iceberg and sea water are 0.9 and 1.03 respectively. The percentage of total volume of the iceberg below the sea water surface is

  1. 8.738%
  2. 87.38%
  3. 78.38%
  4. 7.38%
Answer
Answer. b

44. A piece of wood having weight 5 kg floats in water with 60% of its volume in the liquid. The specific gravity of wood is

  1. 0.5
  2. 0.4
  3. 0.83
  4. 0.6
Answer
Answer. d

45. The increase in metacentric height

  1. Increase stability
  2. Decrease stability
  3. Increases comfort for passengers
  4. Decreases comfort for passengers

The correct answer is

  1. i and iv
  2. i and iii
  3. ii and iv
  4. ii and iii
Answer
Answer. a

46. The point, through which the whole weight of the body acts, irrespective of its position, is known as

  1. centre of percussion
  2. centre of mass
  3. moment of inertia
  4. centre of gravity
Answer
Answer. d

47. An object weighs 100 N in air and 75 N in water when fully submerged in it. The specific gravity of the object is

  1. 2.5
  2. 4.0
  3. 1.25
  4. 4.5
Answer
Answer. b

48. For passenger ships in sea, the metacentric height is kept

  1. as small as possible
  2. as large as possible
  3. not to0 much high not too much small
  4. can’t say
Answer
Answer. a

49. A solid cylinder of length L and diameter D and specific gravity 0.6 floats in neutral equilibrium in water with its axis vertical. What is ratio of L to D?

  1. $\sqrt{\frac{3}{2}}$
  2. $\frac{2}{\sqrt{5}}$
  3. $\frac{4}{5\sqrt{3}}$
  4. $\frac{5}{4\sqrt{3}}$
Answer
Answer. d

50. If the metacentric heights of two floating bodies A and B are 1 m and 1.5 m, then which of the following is a correct statement?

  1. The body A is more stable than body B
  2. The body B is more stable than body A
  3. The bodies A and B have equal stability
  4. The bodies A and B are unstable
Answer
Answer. b