# Hydraulics and Fluid Mechanics – Section 1

41. The body will sink down if the force of buoyancy is __________ the weight of the liquid displaced.

A. equal to
B. less than
C. more than

42. If a body floating in a liquid returns back to its original position, when given a small angular displacement, the body is said to be in

A. neutral equilibrium
B. stable equilibrium
C. unstable equilibrium
D. none of these

43. The pressure measured with the help of a piezometer tube is in

A. N/mm2
B. N/m2
D. all of these

44. The power transmitted through a pipe is (where w = Specific weight in N/m3, and Q = Discharge in m3/s)

A. w x Q x H
B. w x Q x hf
C. w x Q (H – hf)
D. w x Q (H + hf)

Correct Answer: C. w x Q (H – hf)

45. In an external mouthpiece, the absolute pressure head at vena contracta is __________ the atmospheric pressure head by an amount equal to 0.89 times the height of the liquid, above the vena contracta.

A. less than
B. more than

46. The weight per unit volume of a liquid at a standard temperature and pressure is called

A. specific weight
B. mass density
C. specific gravity
D. none of these

47. The center of buoyancy is the center of the area of the immersed body.

A. Correct
B. Incorrect

48. The metacentric heights of two floating bodies A and B are 1 m and 1.5 m respectively. Select the correct statement.

A. The bodies A and B have equal stability
B. The body A is more stable than body B
C. The body B is more stable than body A
D. The bodies A and B are unstable

Correct Answer: C. The body B is more stable than body A

49. In open channels, the specific energy is the

A. total energy per unit discharge
B. total energy measured with respect to the datum passing through the bottom of the channel
C. total energy measured above the horizontal datum
D. kinetic energy plotted above the free surface of the water

Correct Answer: B. total energy measured with respect to the datum passing through the bottom of the channel

50. The Bernoulli’s equation is based on the assumption that

A. there is no loss of energy of the liquid flowing
B. the velocity of flow is uniform across any cross-section of the pipe
C. no force except gravity acts on the fluid
D. all of the above

Correct Answer: D. all of the above