11,
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26,

Section B
Answer all questions in two or three sentences.

Each question carries 2 marks.
Define ultimate strength or the tensile strength of the wire.
What is meant by twisting couple ?
What are damped and forced oscillations ?
Obtain the differential equation representing the oscillations of a driven harmonic oscillatoy
What is a plane progressive harmonic wave ?
State Fourier theorem.

State and define unit of sound intensity.
(7 x2=14 Mar}.

Section C

Answer any five questions in one paragraph.
Each question carries 4 marks.

Derive the expression for the period of oscillation of a torsion pendulum.
(a). Derive an expression for the bending moment.
(b) Why the girders are I-section form ?
What is anharmonic oscillator ? Derive an expression for the time period of oscillation of a
anharmonic oscillator,
Assuming the results of forced oscillations, discuss the sharpness of resonance.
Discuss the cases of critical damping and under damping.
Discuss the modes of transverse vibrations of a string.
What are the requirements of a good auditorium ?
(5 x 4 = 20 mark
Section D

Solve any four problems.
Each question carries 4 marks.

A metal disc of diameter 0.1 m. and mass 1.2 kg. is fixed symmetrically to the lower end of:
torsion wire of length 1 m. and diameter 1.44 x 10° m., the upper end of which is fixed. The tix
period of torsional oscillation is 1.98 seconds. Calculate the rigidity modulus of the material of th:
wire. .

A metal bar 0.01 m. square in section and 0.6 m. long is firmly clamped horizontally at one ec:
and a weight of 1.4 kg. is applied at the free end. Calculate the depression produced. Young:
modulus of the material = 9.9 x 10!° Nm-2.

Calculate the displacement of a body executing simple harmonic motion in terms of its amplituc:
at which the KE = 3 x PE.