Download PTU (Punjab Technical University) B.Tech (Bachelor of Technology) / BE (Bachelor of Engineering) 2021 January EEE 3rd Sem 76385 Engineering Mechanics Previous Question Paper
Total No. of Pages : 03
Total No. of Questions : 18
B.Tech. (EE/Electrical & Electronics Engg.) (2018 Batch)
B.Tech. (Electronics & Electrical Engg.) (2018 Batch) (Sem.?3)
ENGINEERING MECHANICS
Subject Code : BTXX-XXX-18
M.Code : 76385
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.
Explain Eular's law?
2.
Explain Scalar quantities.
3.
What are rigid bodies? Explain.
4.
Define a Free Body Diagram. Give two examples.
5.
A body of mass 7.5 kg is moving with a velocity of 1.2 m/s. If a force of 15 N is applied on
the body, determine its velocity after 2 s.
6.
What do you understand by D'Alembert's principle?
7.
Explain :
a. Coefficient of friction
b. Cone of friction.
8.
Explain parallel and perpendicular axis theorem.
9.
Define gyroscope.
10. Explain law of coulomb friction.
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SECTION-B
11. Explain Symmetric and anti-symmetric tensor.
12. In the engine system shown in Fig.1, the crank AB has a constant clockwise angular
velocity of 2000 rpm. For the crank position indicated, determine
a. Angular velocity of the connecting rod BD
b. The velocity of piston P.
B
i= 200 mm
t = 75 mm
C
40?
A
P
D
FIG.1
13. A uniform ladder of weight 800 N and of length 7 m rests on a horizontal ground and leans
against a smooth vertical wall. The angle made by the ladder with the horizontal is 60?.
When a man of weight 600 N stands on the ladder at a distance 4 m from the top of the
ladder, the ladder is at the point of sliding? Determine the coefficient of friction between
the ladder and the floor.
14. Find the radius of gyration of a triangle whose base is 40mm and height is 60mm about an
axis passing through C.G. and parallel to base (Fig.2).
FIG.2
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15. A dynamics instructor demonstrates gyroscopic principles to his students. He suspends a
rapidly spinning wheel with a string attached to one end of its horizontal axle. Describe the
precession motion of the wheel.
SECTION-C
16. a. Distinguish kinematics & kinetics.
b. Drive expression of the angular momentum of a system of point.
17. A beam ABCDEF of 7.5 m long and span 4.5 m is supported at B and E. The beam is
loaded as shown in Fig.3. Find the support reactions at the two supports.
FIG.3
18. A solid steel shaft transmits 200 kW at 300 rpm. Determine the suitable diameter of the
shaft if the maximum torque transmitted exceeds the mean 15% in each revolution. The
shear stress is not to exceed 60 MPa. Also find the maximum angle of twist in a length of
4 m of the shaft. G = 80 GPa.
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