Download PTU (Punjab Technical University) B.Tech (Bachelor of Technology) / BE (Bachelor of Engineering) 2021 January Automation-And-Robotics 3rd Sem 76504 Kinematics And Theory Of Machines Previous Question Paper
Total No. of Pages : 03
Total No. of Questions : 18
B.Tech. (Automation & Robotics) (2018 Batch) (Sem.?3)
KINEMATICS AND THEORY OF MACHINES
Subject Code : BTAR-305-18
M.Code : 76504
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 :
1.
Differentiate between flexible link and fluid link.
2.
Differentiate between lower pair and higher pair.
3.
What is the significance of degrees of freedom of a kinematic chain when it functions as a
mechanism? Give examples.
4.
State the `Aronhold Kennedy's Theorem' of three instantaneous centres.
5.
What is the Coriolis acceleration component?
6.
Why a roller follower is preferred to that of a knife-edged follower?
7.
Explain the terms :
a) Module
b) Pressure angle
8.
Differentiate between epi-cycloid and hypo-cycloid.
9.
What do you understand by Laws of friction?
10. Explain transmission angle of a mechanism.
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SECTION-B
11. A crank and slotted lever mechanism used in a shaper has a centre distance of 300 mm
between the centre of oscillation of the slotted lever and the centre of rotation of the crank.
The radius of the crank is 120 mm. Find the ratio of the time of cutting to the time of return
stroke.
12. Using relative velocity approach find the velocity of point D in Fig. 1, 2 =20 rad/sec.
O2O4 = 350 mm, BD = 160 mm
O2B = 140 mm, CD = 100 mm
BC = 250 mm, O4C = 210 mm
D
C
3
B
4
2 = 20 rad/sec
2
O2
O4
FIG.I
13. Derive an expression for minimum number of teeth required on a pinion to avoid
interference when it gears with a rack.
14. Find the force required to move a load of 300 N up a rough plane, the force being applied
parallel to the plane. The inclination of the plane is such that a force of 60 N inclined at 30?
to a similar smooth plane would keep the same load in equilibrium. The coefficient of
friction is 0.3.
15. Explain the following :
a) Angle of friction.
b) Coefficient of friction.
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SECTION-C
16. A cam drives a flat reciprocating follower in the following manner :
During first 120? rotation of the cam, follower moves outwards through a distance of
20 mm with simple harmonic motion. The follower dwells during next 30? of cam rotation.
During next 120? of cam rotation, the follower moves inwards with simple harmonic
motion. The follower dwells for the next 90? of cam rotation. The minimum radius of the
cam is 25 mm. Draw the profile of the cam.
17. An Epicyclic gear train, as shown in Fig. 2, has a sun wheel S of 30 teeth and two planet
wheels P-P of 50 teeth. The planet wheels mesh with the internal teeth of a fixed annulus
A. The driving shaft carrying the sunwheel, transmits 4 kW at 300 r.p.m. The driven shaft
is connected to an arm which carries the planet wheels. Determine the speed of the driven
shaft and the torque transmitted, if the overall efficiency is 95%.
A
P
Arm
S
P
FIG.2
18. Write notes on :
a) Acceleration in the Slider Crank Mechanism
b) Kinematic Chain
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 26 June 2021