# Strength of Materials Questions and Answers – Stresses in frames – 2

This set of Strength of Materials Quiz focuses on “Stresses in frames – 2”.

1. The Velocity at which flow changes from viscous to turbulent is called __________ velocity.
a) Critical
b) Frictional
c) Relative
d) Nominal

Explanation: A fluid motion is always subjected to a certain resistance. In reality, this resistance is mainly due to sliding. The velocity at which the flow changes from a viscous flow to turbulent flow is called critical velocity.

2. Flow in circular pipes will be turbulent is Reynolds number is _________
a) < 2800
b) > 2800
c) = 2800
d) ~ 2800

Explanation: Reynold’s number (Re) = Vd/v
V = Mean velocity of flow in pipe
d = Diameter of pipe
v = Kinematic viscosity of liquid
Flow in circular pipe will be turbulent if Reynolds number is greater than 2800.

3. _____ number is the ratio between inertia and viscous forces.
a) Lamina’s
b) Parker’s
d) Reynold’s

Explanation: Professor Reynold’s deduced from his experiments that at lower velocities the liquid flow was a laminar and at higher velocities, the flow was turbulent. It is a dimensionless number as it is the ratio between inertia and viscous forces.

4. The frictional resistance is ______ to the surface area of contact.
a) Inversely proportional
b) Directly proportional
c) Equal
d) Not equal

Explanation: The frictional resistance is directly proportional to the surface area of contact. The frictional resistance is independent of the pressure and where is considerably with temperature.

5. ___________ flow the liquid particles move along straight parallel paths.
c) Laminar
d) Turbulent

Explanation: Flow in circular pipes will be laminar if the Reynolds number is less than 2000. The laminar flow is a type of flow in which the liquid particles move along straight parallel path in layers or laminates.
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6. The __________ resistance is independent of the nature of surface contact.
a) Frictional
b) Skid
c) Shear
d) Coupling

Explanation: When the liquid flows at a velocity that is less than the critical velocity. A thin stationary film of the liquid is formed on a supporting surface. This is a reason that the frictional resistance is independent of the nature of surface of contact.

7. Calculate the specific weight of oil. If the specific gravity is 0.95. Take specific weight of water is 1000 kg/m3.
a) 750 kg/m3
b) 850 kg/m3
c) 950 kg/m3
d) 1250 kg/m3

Explanation: The specific gravity (S) = specific weight of oil / specific weight of
Specific weight of oil = S × specific weight of water
Specific weight of oil = 0.95 × 1000
= 950 kg/m3.

8. In _______ liquid flows under atmospheric pressure.
a) Pipe flow
b) Open channel
c) Stream
d) Aqueduct

Explanation: Liquid flows under atmospheric pressure in an open channel due to its slope of the channel. There must be some slope in the bed of the channel to flow to take place.

9. The energy gradient line is _______ to drop in bed, in an open channel.
a) Equal
b) Parallel
c) Perpendicular
d) Unequal

Explanation: For uniform flow in an open channel the drop in the energy gradient line is equal to drop in bed. Flows in irrigation channels, streams and rivers are some examples of open channel flow.

10. Aqueduct is an example of __________ channel.
a) Natural
b) Prismatic
c) Non prismatic
d) Artificial

Explanation: An artificial channel is the one which is built artificially for some specific purpose such as irrigation water supply and water power development etc. The examples include canals, drainage gutters and aqueducts.

11. Rectangular channel is _________ channel.
a) non Prismatic
b) Prismatic
c) Natural
d) Artificial

Explanation: A channel is said to be prismatic if the cross-section is uniform and the bed slope is constant throughout its length. The rectangular channel comes under Prismatic channel.

12. Expand RVF _________
a) Rapid Vary Fluid
b) Rise in Virtual Flow
c) Rapidly Varied flow
d) Rapidly Viscous flow

Explanation: RVF stands for Rapidly Varied Flow. If the depth floor changes abruptly over a comparatively shorter distance, the flow is characterised as rapidly varied flow. Typical examples of rapidly varied flow are hydraulic jump and hydraulic drop.

13. Froude number is the ratio of inertial force to the _________ force.
a) Shear
b) Gravity
c) Uplift
d) Viscous

Explanation: The ratio of the inertia force and gravity force is known as the Froude number. It is denoted by Fr.
Fr = V/(gD)1/2.

14. For super critical flow, Fr _________ 1.
a) >
b) <
c) =
d) ~

Explanation: Froude number the ratio of inertial force to the gravity force.
Fr = V/(gD) 1/2
For supercritical flow, Fr > 1.

15. Strut is a tension member.
a) True
b) False

Explanation: Strut is the member of a structure any position carrying the compressive load. It may be horizontal, inclined or even vertical.

Sanfoundry Global Education & Learning Series – Strength of Materials.

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