LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – PHYSICS

FG 05

SECOND SEMESTER – APRIL 2008

PH 2500 – MECHANICS & SOUND

 

 

 

Date : 23/04/2008                Dept. No.                                        Max. : 100 Marks

Time : 1:00 – 4:00

SECTION – A

Answer all the questions.                                                                    10×2 = 20 Marks

 

1. Two ships A and B are sailing due east and due south with velocities 30km/hr and 40km/hr respectively. Find the velocity of ship A relative to the ship B.
2. What is the physical significance of moment of inertia?
3. Define: (i) Metacentre and (ii) Metacentric height.
4. Show that the algebraic sum of the moments of two forces forming a couple is equal to the moment of the couple.
5. What is meant by phase space?
6. Distinguish between holonomic and non-holonomic constraints.
7. What are Lissajous’ figures? Mention their uses.
8. What are beats? Mention their applications.
9. Explain piezo-electric effect.
10. What is absorption co-efficient? Mention its unit.

 

SECTION – B

Answer any four questions.                                                               4×7.5 = 30 Marks

11. Obtain an expression for the acceleration of a body rolling down an inclined plane.
12. (a) Describe the working of venturimeter.
    • The diameter of the throat of a venturimeter is 0.05m. When it is inserted in a horizontal pipe line of diameter 0.1m, the pressure difference between the pipe and the throat equals 0.06m of water.  Calculate the rate of flow of water.
13. Define the Hamiltonian. Obtain Hamilton’s canonical equations for a holonomic system.
14. Describe Melde’s experiment to determine the frequency of a vibrator.
15. Explain the production of ultrasonics by magnetostriction method.

 

 

 

 

SECTION-C

Answer any four questions.                                                               4×12.5 = 50 Marks

16. (a) Derive an expression for the moment of inertia of a solid sphere about its diameter.

(b)        Find ratio of radius of gyration of a circular disc to that of circular ring of the same radius about the diameter.

17. (a) Define centre of pressure.

• Determine the position of centre of pressure for a triangular lamina of height h immersed vertically in a liquid with,
• its vertex and

(ii)  its base in the surface of the liquid.

18. Derive Lagrange’s equations of motion and apply them to the Atwood’s machine to find the

acceleration of the system.

19. (a) Derive an expression for the velocity of longitudinal waves in a gas. Discuss Laplace’s correction.

• The velocity of sound in air at 15˚C is 340m/s. What will it be when the pressure of the gas is doubled and its temperature is raised to 160˚C?

20. Define reverberation time. Derive Sabine’s formula for the reverberation time.

 

 

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LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc. DEGREE EXAMINATION – PHYSICS

XC 04

SECOND SEMESTER – April 2009

PH 2500 – MECHANICS & SOUND

 

 

 

Date & Time: 23/04/2009 / 1:00 – 4:00       Dept. No.                                                       Max. : 100 Marks

 

 

PART – A

Answer ALL questions:                                                                                     (10×2=20 Marks)

 

1. State the parallel axes theorem of moment of inertia.
2. Two cars A &B are moving with velocities 24km/hr and 32km/hr due east and north

respectively. Find the relative velocity.

3. Define centre of gravity.
4. State the laws of floatation.
5. What are holonomic and nonholonomic constraints?
6. Define conservative and non conservative systems.
7. A tuning fork A produces 4 beats/sec with a tuning fork of frequency 256 Hz. The fork A is filed and the

beats occur at shorter intervals. What was its original frequency?

8. State the laws of vibrations of a transverse string.
9. What is piezoelectric effect?
10. A hall of volume 4500m³ is found to have a reverberation time of 2.37 sec. If the sound

absorbing surface of the hall has an area of 750m², calculate the absorption coefficient.

 

PART – B

Answer any FOUR questions:                                                                          (4×7.5=30 Marks)

 

11. Show that the path of a projectile is a parabola.
12. Find out the position of the centre of gravity of a hollow hemisphere.
13. Apply Lagrange’s equations of motion to the Atwood machine to find out the acceleration

of the system.

14. Discuss the effect of pressure, temperature and density on the velocity of sound.
15. Describe the magnetostriction method of producing ultrasonic waves.

 

PART – C

Answer any FOUR questions:                                                                         (4×12.5=50 Marks)

 

16. a) Obtain an expression for the acceleration of a body rolling down an inclined plane

without slipping.                                                                                                              (8.5)

1. b) Discuss the above result for the cases of solid sphere and solid cylinder. (4)
2. Find the location of the centre of pressure of a triangular lamina immersed in a liquid

with its (i) vertex and (ii) base, touching the surface of the liquid.                               (6+6.5)

18. a)Derive the equation of motion for a simple pendulum, using Lagrangian method.     (6)

b)State Hamiltonian principle and obtain Hamiltonian equations of motion.                  (6.5)

19. Discuss the composition of two simple harmonic motions acting along (i) a straight line

and (ii) at right angles.                                                                                                   (5+7.5)

20. a) Define reverberation time and explain the use of Sabine’s formula. (2+4.5)
21. b) Discuss the condition for good a acoustical design of an auditorium. (6)

 

 

 

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