LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – MATHEMATICS
SIXTH SEMESTER – APRIL 2011
MT 6604/MT 5500 – MECHANICS – II
Date : 07-04-2011 Dept. No. Max. : 100 Marks
Time : 9:00 – 12:00
PART – A
Answer ALL the questions: (10 x 2 =20)
- What is the Centre of Gravity of a compound body?
- Where does the C.G of a uniform hollow right circular cone lie?
- Define virtual work.
- What is common catenary?
- Show that frequency is the reciprocal of the periodic time in a simple harmonic motion.
- If the maximum velocity of a particle moving in a simple harmonic motion is
2ft/sec and its period is 1/5 sec, prove that the amplitude is feet.
- What is the p–r equation of a parabola and an ellipse?
- What are the radial and transverse components of acceleration?
- Define moment of inertia?
- Explain the conservation of angular momentum.
PART –B
Answer any FIVE questions: (5 x 8 = 40)
- A homogenous solid is formed of a hemisphere of radius r soldered to a right circular cylinder of
the same radius. If h be the height of the cylinder, show that the center of gravity of the solid from
the common base is .
- Find the center of gravity of a uniform trapezium lamina.
- A uniform rod AB of length 2a with one end A against a smooth vertical wall being supported by
a string of length 2l, attached to the other end of the rod B and to a point C of the wall vertically
above A. Show that if the rod rests inclined to the wall at an angle q, then cos2 q =.
- Derive the intrinsic equation of the common catenary.
- A second pendulum is in a lift which is ascending with uniform acceleration . Find the number of seconds it will gain per hour. Calculate the loss if
the lift were descending with an acceleration of .
- Show that the composition of two simple harmonic motions of the same period
along two perpendicular lines is an ellipse.
- Prove that the areal velocity of a particle describing a central orbit is constant.
Also show that its linear velocity varies inversely as the perpendicular distance
from the centre upon the tangent at P.
- Show that the Moment of inertia of a truncated cone about its axis, the radii of its
ends being a and b, (a<b) is .
PART –C
Answer any TWO questions: (2 x 20 = 40)
- (a) Find the centre of gravity of the area in the first quadrant bounded by the co-
ordinate axes and the curve .
(b) AB and AC are two uniform rods of length 2a and 2b respectively. If
, prove that the distance from A of the Centre of gravity of two the
rods is (10 + 10)
- (a) Show that the length of a chain whose ends are tied together and hanging over
a circular pulley of radius a, so as to be in contact with two thirds of the
circumference of the pulley is a .
(b) Derive the expression for velocity and acceleration of a particle moving on a
curve. (10 + 10)
- (a) A particle P describes the orbit under a central force. Find the
law of force.
(b) The law of force is and a particle is projected from an apse at a distance
Find the orbit when the velocity of projection is . (10 + 10)
- (a) State and prove Parallel axis theorem.
(b) Find the lengths of the simple equivalent pendulum, for the following:
- i) Circular wire ii) Circular disc. (10 + 10)
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