Quiz: Mechanical Engineering 06 Aug 2020

Quiz: Mechanical Engineering
Exam: UPPSC AE
Topic: Miscellaneous

Each question carries 3 mark.
Negative marking: 1 mark
Time: 10 Minute

Q1. Which one of the following is the desirable section for torsional loading conditions?
(a) angle Section
(b) Channel Section
(c) I-section
(d) Box-type section

Q2. If the load at the free end of a uniform cantilever beam is increased, then failure will occur
(a) at the middle
(b) at the fixed end
(c) at the point of application of load
(d) anywhere in the span

Q3. Which of the following term is used for Proof resilience per unit volume of a material?
(a) resilience
(b) modulus of elasticity
(c) modulus of resilience
(d) toughness

Q4. Mushroom follower is also known by another name that is
(a) flat faced follower
(b) Spherical faced follower
(c) Roller follower
(d) Knife edge follower

Q5. A governor is said to be stable if
(a) Radius of rotation of ball decreases as the equilibrium speed decreases
(b) Radius of rotation of balls increases as the equilibrium speed decreases
(c) Radius of rotation of balls increases as the equilibrium speed increases
(d) Radius of rotation of balls decreases as the equilibrium speed increases

Q6. Which of the following is correct for Axode?
(a) Locus of Instantaneous axis
(b) Axis parallel to Instantaneous axis
(c) Axis perpendicular to Instantaneous axis
(d) Instantaneous axis

Q7. Which of the following mechanism work behind when the auto rickshaw takes a turn?
(a) It has a differential mechanism
(b) The tyres slip during turns
(c) Power is transmitted to only one of the wheels
(d) None of these

Q8. Which of the following statement is correct for critical damping?
(a) It provides basis of determining critical damping.
(b) It predicts nature of vibration
(c) It provides a measure of the relative amount of damping in a system.
(d) It enables measurement of damping.

Q9. How the shock absorbing capacity of a bolt can be increased?
(a) Tightening it properly
(b) Increasing shank diameter
(c) Grinding the shank
(d) Using washer

Q10. The pressure head loss experienced by fluid flow due to friction in a pipe reduces with
(a) increasing length of pipe
(b) increasing diameter of pipe
(c) decreasing length of pipe
(d) both b and c

Solutions

S1. Ans.(d)
Sol. When torsion is dominant then Box-type section used & second most probable section for torsion dominant is I Section because the shear center of these section not lies outside.

S2. Ans.(b)
Sol. If the load at the free end of a cantilever beam is increased the failure will occur at the fixed end because due to increase of load moment resisted by fixed support is increased and when support moment reaction increased beyond its limit then failure occur.

S3. Ans.(C)
Sol. Proof resilience is defined as the maximum energy that can be absorbed up to the elastic limit, without creating a permanent distortion. The modulus of resilience is defined as the maximum energy that can be absorbed per unit volume without creating a permanent distortion.

S4. Ans.(a)
Sol. Flat faced follower is also known as mushroom follower
Types of followers –
1. Knife edge follower
2. Roller follower
3. Flat faced or mushroom follower
4. Spherical follower

S5. Ans.(c)
Sol. If each speed of governor possesses a particular radius of governor, then it is called stable governor.

S6. Ans.(a)
Sol. The instantaneous center changes every moment, its locus is called centrode and the surface generated by the instantaneous axis is called the axode.

S7. Ans.(b)
Sol. Rickshaws takes sharp turn by using the concept of slip. When one of the wheels will slip against the road, rickshaw turns.
We cannot use a differential mechanism in it because wheels and axis are rigidly connected to each other.

S8. Ans.(b)
Sol. for critical damping (ς=1)
It is used to predicts the nature of vibration.

S9. Ans.(c)
Sol. There are following ways to increase shock absorbing capacity of a bolt.
Shock absorbing capacity or strain energy (U)
∪ ∝ l(length of bolt)
∪ ∝ 1/A
Or
∪ ∝ 1/d^2
Hence, L↑→∪↑
d↑→∪↓

S10. Ans (d)
Sol. We know that pressure head loss in a pipe is given by Darcy-Weisbach’s equation.
h=(fLV^2)/(d.2g)
Here, h decreases with increasing diameter and decreasing length of the pipe.

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