JPSC Assistant Engineer 2021: Assistant Engineer Written Exam, Advt. No. 08/2018 and 08/2019, MECHANICAL ENGINEERING PAPER-II SUBJECT-CODE-11
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AEUD
REcllAr`ITCAL ENGINEERING
PAPER - 11
SUBJECT CODE : 11
Full Marks : 200 Time : 3 Hours
Instructions For Cand.idates :
PleasereedeachOfthefollowingiustructionscarefuilybeforeat[emplingquestious.
(I) A:rlswers must be written in ENGLISH only.
a) The question paper contains a total Of 8 questions in TWO Section : Section-A
and Section-B. qlouR questions in each section)
(3) Question No.1 Of section `A' and QuestionNo. 5 Of section `B' are comi)ulsory.
(4) Candidates have to attempt another THREE questions from remaining SIX
questions choosing atleast ONE question from each section.
(5) Assume suitable data if i ;ound necessary.
(6) Wherever ariy assumption be made i;or answering a question, they must be
clearly indicated,
q) Marks carried by a question / section is indicated against it.
(8) Unless struck of i attempt of question shall be counted even if attemptedpartly.
(9) Any page or portion of the page lef i blank in the A:rlswer Booklet must be clearly
struck off
SHCTION-A Marks
5 x 8 - 40
1. (a) What is true stress and true strain? Derive relationship for true stress and strain
in terms of engineering stress and sti-air.
a) Derive an expression for Euler's critical load for the case of buckling of pin
ended col-
(c) Derive expression for torque requirement for lifting load in a power screw.
(d) What is center of percussion ? How we can calculate center of percussion of a
compound pendulum ?
(e) Write a note on simple, compound, planetary gear train.
AEUD (11) Paper-II
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Marks
2. A circular rod of50 mm diameter is subjected to load as shown in figure. Deterrine
the nature and magnitude of stresses at point A and 8. 40
3000 N
A, i
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8 \1 kNm
15kN
250 rm
A horizontal shaft AD supported in bearing at A and a and carrying pulleys at C and
D is to transmit 75 kw at 500 rpm from drive pulley D to off-take pulley C, as shown
in figure. Calculate the dianeter of shaft. The data given is P, = 2P2 and Qi = 2Q2,
radius of pulley C is 220 rmi radius of pulley D isl60 mnL allowable shear stress is
45 rna. 40
CD
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A 8
I I
I
600 I- 600 `L 300 I
I-
4. Discuss in detail constant acceleration and deceleration follower motion using
necessary derivations and diagram. Comment and show the nature of displacement,
velocity, and acceleration curve of such motion. 40
SECTION - 8 5 x 8 - 40
(a) Write short notes on large-particle composites and fibre-reinforced composite.
a) Show atomic packing factor for the FCc crystal is o.74.
iREUD (11) Paper-H
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Marks
(c) Write a short note on centreless grinding using suitable sketches.
(d) Discuss gating-system design.
(e) Write anote on precipitation hardening.
6. (a) State and describe in detail thee differentmechanisms of strengthening inmetals.
a) Describe recovery, recrystauization and grain growlh. How tensile strength and
ductilityvaryduringrecovery,recrystallizationandgraingrowth?
In an orthogonal cutting test with a tool of rake angle loo, the following observations
were made :
Chip -thickness ratio = 0.3
Horizontal component of the cutting force = 1290 N
Vertical component of the cutting force = 1650 N
From the Merchant' s theory, calculate the various components. of the cutting forces
40
and the coefficient of friction at the chip-tool interface.
8. Solve following problem using simplex method
Minimize f = 40Xi -100X2
Subject to
lout + 5pe2 s 25oo
4x] + 1 or2 i 2ooo
2x, + 3X2 S 900
xl 2 0 I,2 2 0
40
Further comment on nature of solution.
Paper-II
AEUD (11)Official key not published for this paper.
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Source: Jharkhand Public Service Commission. Question paper published by Jharkhand Public Service Commission.