PTU Punjab Technical University B-Tech May? 2019 Question Papers 1st Semester May Civil Engineering (CIV)
Total No. of Pages : 02
Total No. of Questions : 09
B.Tech (Civil Engg.) (2018 Batch) (Sem.?1,2)
MECHANICS OF SOLIDS
Subject Code : BTPH-101-18
M.Code : 75351
Time : 3 Hrs. Max. Marks : 60
INSTRUCTIONS TO CANDIDATES :
1.
SECTION-A is COMPULSORY consisting of TEN questions carrying T WO marks
each.
2.
SECTION - B & C. have FOUR questions each.
3.
Attempt any FIVE questions from SECTION B & C carrying EIGHT marks each.
4.
Select atleast T WO questions from SECT ION - B & C.
SECTION-A
1.
Write briefly :
(2?10=20)
a) Give the physical significance of gradient, divergence and curl of a field.
b) Distinguish between conservative and non-conservative forces.
c) Define Coriolis force.
d) Distinguish between heavy, critical and light damping.
e) Define quality factor for damped oscillations.
f) Explain the concept of centre of mass.
g) State theorems of parallel axes and perpendicular axes for moment of inertial.
h) Write Euler's equations of motion.
i) Write the laws of limiting friction.
j) Explain stress-strain curve.
SECTION-B
2.
a) Express gradient, divergence and curl of a field in spherical coordinates.
5
b) Find constants a, b and c so that the vector A = (x+2y+az)i +(bx?3y?z)j+(4x+cy+2z)k
is irrotational, where i, j, k are rectangular unit vectors.
3
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3.
a) State Newton's laws of motion and discuss their limitations in describing particle
motion.
4
b) Discuss about the conservation of angular momentum and energy during the motion
of a body.
4
4.
a) Derive a general differential equation of motion for a simple harmonic oscillator and
obtain its solution.
5
b) The total energy of particle executing a S.H.M. of period 2 seconds is 10.24?10?4
Joule. The displacement of a particle at /4 second is 0.082m. Find the amplitude
and mass of the particle.
3
5.
a) Explain free vibrations, damped vibrations, forced vibrations and resonance, giving
one example of each.
4
b) Find the maximum velocity and acceleration of a particle executing S.H.M. of period
10 seconds and amplitude 5?10?2m.
4
SECTION-C
6.
a) Define a rigid body. Prove that the total internal forces and torques for these forces
are always zero.
4
b) Prove that angular momentum of a system of particles can be expressed as the sum of
angular momentum of the system of centre of mass and angular momentum of system
about the centre of mass.
4
7.
a) Derive the expression for moment of inertia of a plane lamina about an axis lying in
its plane parallel to one of its sides and passing through its centre of mass.
4
b) A uniform thin bar of mass M and length L is bent to make a square. Calculate its
moment of inertia about an axis passing through the centre of mass perpendicular to
the square thus formed.
4
8.
a) Define angle of friction and angle of repose (with neat diagrams) and derive relation
between them.
4
b) "Friction is a necessary evil", comment on this statement. Give some methods to
reduce friction.
4
9.
a) Distinguish between the concepts of elasticity and plasticity with appropriate
examples.
4
b) Differentiate between bending moment and twisting moment.
4
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 04 November 2019