# Fluid Mechanics Questions and Answers

**Fluid Mechanics Questions and Answers**

**1-An ideal flow is**

(A) Viscous and compressible

(B) Inviscid and compressible

(C) Viscous and incompressible

(D) Inviscid and incompressible

**2-Newton’s law of viscosity states that**

(A) stress is proportional to strain

(B) stress is proportional to rate of strain

(C) stress is inversely proportional to strain

(D) stress is inversely proportional to rate of strain

**3-Reynolds number is the ratio of**

(A) Inertia force / Elastic force

(B) Inertia force / Viscous force

(C) Buoyancy force / Viscous force

(D) Buoyancy force / Inertia force

**4-Moody diagram in fluid mechanics shows the relation between**

(A) Friction factor and Reynolds number

(B) Heat transfer coefficient and Reynolds number

(C) Drag coefficient and Mach number

(D) Coefficient of discharge and Mach number

**5-Boundary layer separation is caused by**

(A) Reduction of pressure in the direction of flow

(B) Reduction of the boundary layer thickness

(C) Pressure of adverse pressure gradient

(D) Presence of favourable pressure gradient

**6-For laminar flow through a pipe, the discharge varies**

(A) As the square of diameter

(B) As the inverse of viscosity

(C) As the square of viscosity

(D) Inversely as the square of diameter

**7-Velocity at a point in pipe flow may be measured by installing**

(A) a wall tap

(B) a Venturimeter

(C) static pitot tube

(D) Rotameter

**8-Inertia to gravity force ratio gives a non dimensional number called**

(A) Reynolds number

(B) Froude number

(C) Cauchy number

(D) Mach number

**9-The pipe carrying water from reservoir to the turbine house in a hydraulic power plant is called **

(A) Supply pipe

(B) Inlet pipe

(C) Pen stock

(D) Draft tube

**10-Kinematic viscosity is defined as equal to **

(A) Dynamic viscosity x Density

(B) Dynamic viscosity / Density

(C) Dynamic viscosity x Pressure

(D) Pressure x Density

**11-Surface tension has unit of**

(A) Force per unit area

(B) Force per unit length

(C) Force per unit volume

(D) None of the above

**12-Pascal’s law states that pressure at a point is equal in all directions**

(A) In a liquid at rest

(B) In a fluid at rest

(C) In a laminar flow

(D) In a turbulent flow

**13-Atmospheric pressure held in terms of water column is**

(A) 2.8 meters

(B) 8.3 meters

(C) 9.8 meters

(D) 10.3 meters

**14-Mach number is defined as the ratio of **

(A) Inertia force to viscous force

(B) Viscous force to surface tension force

(C) Viscous force to elastic force

(D) Inertia force to elastic force

**15-Total drag on a body is the sum of**

(A) Pressure drag and velocity drag

(B) Pressure drag and friction drag

(C) Friction drag and velocity drag

(D) None of the above

**ANSWERS:**

1-(D), 2-(B), 3-(B), 4-(A), 5-(C), 6-(B), 7-(C), 8-(B), 9-(C), 10-(B), 11-(A), 12-(B), 13-(D), 14-(D), 15-(B)