Download PTU (I.K.Gujral Punjab Technical University (IKGPTU)) B-Tech (Bachelor of Technology) (AE)-Automobile Engineering 2020 December 4th Sem 54123 Mechanics Of Machines Previous Question Paper
Roll No.
Total No. of Pages : 03
Total No. of Questions : 18
B.Tech. (AE) (2012 to 2017) (Sem. ?4)
MECHANICS OF MACHINES
Subject Code : BTAE-402
M.Code : 54123
Time : 3 Hrs. Max. Marks : 60
INST RUCT IONS T O CANDIDAT ES :
1 .
SECT ION-A is COMPULSORY cons is ting of TEN questions carrying TWO marks
each.
2 .
SECT ION-B c ontains F IVE questions c arrying FIVE marks eac h and s tud ents
have to atte mpt any FOUR q ues tions.
3 .
SECT ION-C contains THREE questions carrying T EN marks e ach and s tudents
have to atte mpt any T WO questio ns.
SECTION-A
Write briefly :
Q1 What is the difference between structure and machine?
Q2 What is pressure angle in cam?
Q3 Differentiate between lower and higher pair.
Q4 What is rigid body and how is it differing from resistant body?
Q5 "Slack side of the open belt drive is always on upper side", why?
Q6 What is the difference between pitch point and trace point in cam profile?
Q7 Define the piston effort. List the factors which influence the piston effort.
Q8 What is dynamically equivalent system?
Q9 What is swaying couple?
Q10 Draw free body diagram for Hartnell governor for its extreme positions?
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SECTION-B
Q11 A cast iron flywheel is fitted to a punch press to run at 90 r.p.m and must supply 12000
N-m of energy during l/5th revolution and allow 15% change of speed. The ring speed is
limited to 350 m/min. Find the mean diameter, mass of flywheel and the motor power.
Assume overall efficiency as 80%.
Q12 A casting having a mass of 100 kg is suspended freely from a rope. The rope makes 2
turns round a drum of 300 mm diameter rotating at 24 rpm. The other end of the rope
pulled by the man. Calculate :
a. Force required by the man
b. Power required to raise the casting and
c. Power supplied by the drum run by prime mover. Take = 0.3.
Q13 A proell governor has equal arms of length 300 mm. The upper and lower end of the arms
are pivoted on the axis of the governor. The extension arm of the lower links is each
80mm long and parallel to the axis when the radii of rotation of the balls are 150 mm and
200 mm. The mass of each ball is 10 kg and central load is 100 kg. Determine range of
speed of the governor.
Q14 a. Two sprockets of chain drive system are 550 mm apart from each other. Determine
the number of teeth on driven sprocket, pitch and length of the chain if driver
sprocket has 20 teeth with 500 mm pitch circle diameter and reduce the speed from
200 rpm to 100 rpm.
b. Calculate the degree of freedom of linkage given if Fig.1
Fig.1
Q15 a. With suitable diagrams explain the various type of constrained motions.
b. In a Crank-slotted lever quick return mechanism, the distance between the fixed
centers is 80mmand the length of the crank is 20mm. Determine the time ratio of
working stroke to the return stroke.
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SECTION-C
Q16 A, B, C and D are four masses carried by a rotating shaft at radii 100 mm, 125 mm,
200 mm and 150 mm respectively. The planes in which the masses revolve are spaced
600 mm apart and the mass of B, C and D are 10 kg, 5 kg and 4 kg respectively. Find the
required mass A and relative angular settings of the four masses so that the shaft shall be
in complete balance.
Q17 Draw the profile of the cam operating a knife edge reciprocating follower and with the
following data; minimum radius of the cam = 25mm Lift = 30mm. The cam lifts the
follower for 120? with simple harmonic motion followed by the dwell period of 30?.
Then the follower suddenly falls to its half of lift and lower down during 150? of the cam
rotation with uniform velocity followed by the dwell period. Cam rotates with speed of
150 rpm.
Q18 The dimensions of four bar link mechanism are AB = 400 mm, BC = 600 mm,
CD = 500 mm, AD = 900 mm and DAB = 60?. AD is a fixed link, E is the point on link
BC such that BE = 200 mm and CE = 400 mm. A force P of 150 N acts at 45? at a
distance of 250 mm from D, as shown in Fig. 2. Another force Q = 100 N acts at E at an
angle of 180?. Find the required input torque on link AB for static equilibrium of the
mechanism.
Q
C
Q 10
= 0
1 N
00N
E
300
300
250
B
3
4
F
400
2
250
P=150N
45?
60
0?
1
A
D
900
Fig.2
NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on
any page of Answer Sheet will lead to UMC against the Student.
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This post was last modified on 13 February 2021