Strength of Materials Questions and Answers – Deflection of Fixed Beam

This set of Strength of Materials Multiple Choice Questions & Answers (MCQs) focuses on “Deflection of Fixed Beam”.

1. In fixed beams, the maximum deflection at __________ is reduced.
a) Centre
b) Supports
d) Through out

Explanation: In fixed beams, the maximum bending moment developed at the centre is reduced. Hence it results in the reduction of deflection of a beam at its centre considerably.

2. Fixing couples means _____
a) End moments
b) Support couples
c) Support moments
d) End supports

Explanation: If the ends are built in, end moments are automatically developed. These moments are called as fixing couples or fixing moments or support moments.

3. Calculate the maximum bending moment in fixed beam for the following figure.

a) 17 kN-m
b) 12.5 kN-m
c) 15.625 kN-m
d) 18 kN-m

Explanation: For a fixed beam, the maximum bending moment is w×l / 8.
Maximum bending moment (M) = 25 × 5 / 8
= 15.625 kNm.

4. _________ is provided to prevent the debris from entering into the penstock.
a) Tash rack
b) Surge tank
c) Anchor blocks
d) Power house

Explanation: Trash rack is a structure which is provided to prevent the debris from entering into the penstock. The trash racks are usually located ahead of the gates. The debris which is collected on the trash rack may be removed either manually or with the help of automatic power driven racks.

5. __________ regulates the speed of turbine.
a) Tail race
b) Anchor blocks
c) Power house
d) Surge tank

Explanation: The surge tank controls the pressure variations in a penstock. Thereby the penstock is protected from effects of water hammer pressure. The surge tank is provided on large penstock to regulate the speed of the turbine.

6. The sheet of water flowing through a notch is called ________
a) Sill
b) Crest
c) Scour
d) Nappe

Explanation: The sheet of water flowing through notch or weir is called as the nappe or vein. The bottom of the notch or the top of the weir over which the water flows is known as the sill.

7. Which of the following is empirical formula coined by Francis?
a) 2.36 LH3/2
b) 1.84 LH3/2
c) 3.34 LH3/2
d) 1.96 LH3/2

Explanation: Francis proposed the following formula for discharge over rectangular weir by assuming Cd = 0.623
Q = 1.84 LH3/2
Where Q = discharge in m3/ s.

8. Calculate discharge of a weir 2 metre long with a water flow over a head of 250 mm use Francis formula.
a) 0.34 m3/s
b) 0.46 m3/s
c) 0.25 m3/s
d) 0.65 m3/s

Explanation: Given that:
Length of weir = L = 2m.
Head over the weir = 0.25 m
Using Francis formula; Q =1.84 LH3/2 = 1.84 × 2×(0.25)3/2.
Q = 0.46 m3/s.

9. 1 litre = ____________ m3.
a) 104
b) 103
c) 10-3
d) 10-4

Explanation: 1 litre = 10-3m3.
For example, Q = 40 lit/min = 40/60 lit/sec = 0.67 × 10-3m3/sec.

10. In cipoletti weir, the side slopes are _______________
a) 1 in 3
b) 1 in 2
c) 1 in 5
d) 1 in 4

Explanation: A trapezoidal weir, which has side slopes of 1 horizontal to 4 vertical, is called as cipoletti weir. The discharge over a cipolletti weir is equal to the discharge over a rectangular Weir without end contractions.

11. The flow of thick oil through a small tube is an example for _________
a) Laminar flow
b) Turbulent flow
c) Rotational flow

Explanation: A flow is said to be laminar when the paths taken by the individual particles do not cross one another. It is also called as streamline flow. The flow of thick oil through a small tube is an example for laminar flow.

12. Flow in rivers is an example of __________ flow.
a) Rotational
b) Laminar
c) Compressible
d) Turbulent

Explanation: A flow is said to be turbulent when the liquid particles move in a zig-zag way and their paths also cross each other. The flow in rivers at the time of floods is a perfect example of turbulent flow.

13. What is the point of contraflexure in a fixed beam of span 5m?
a) 3m
b) 2.75 m
c) 3.75 m
d) 4 m

Explanation: The point of contraflexure from any support be 3×l / 4.
From support A = 3l/4 = 3×5/4 = 3.75 m.
From support B = 3l/4 = 3×5/4 = 3.75 m.

14. Water table should be at least __________ m below subgrade.
a) 1.5m
b) 3 m
c) 1.2 m
d) 2.5 m

Explanation: The top level of water table should be below the level of subgrade. Water table should be at least 1.2 metres below subgrade. If the soil is impermeable, the longitudinal and transverse drains have to be provided to lower the water table.

15. Torsteel is an example of _______
a) Elasticity
b) Plasticity
c) Malleability
d) Ductility

Explanation: Ductility is one of the mechanical properties of materials. It is defined as the property possessed by the material by which material can be drawn into thin wires after undergoing deformation without any rupture. Torsteel is an example of ductility property.

Sanfoundry Global Education & Learning Series – Strength of Materials.

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